Why does furnace blower turn on and off when working properly?

I have a Lennox G24M Elite series furnace. Recently the control panel blower control went out on it neccessitating my having to disconnect the blower and apply direct power to it. Such that it now runs continuously. While I shop around for a new control panel.
Anyway I was wondering if running the main blower all the time would damage it in some way?
Lennox had the moter turning on and off in sync with whether the furnace was on or not and I was wondering what their reasoning for doing it that way might be?
I seem to remember the main blower turning off AFTER the gas had stopped so I don`t think there is any problem in keeping it on after that point. But it did not seem to turn on until AFTER the gas had started. Could there be some greater efficiency to keeping the blower off until AFTER the gas has started? It is also possible that keeping the blower from starting right away gave the smaller combustion air blower a minute or two to get started and to blow away any uncombusted gas before the main blower kicked in.
Any insight on this would be appreciated.

continuous it would not harm anything to run it till you replace the module

which turns the blower on. Similarly they`re is a lag time for the heat exchanger to cool enough to beautifully turn the blower off.

is hot enuogh to start blowing hot air... the fan conbtinues after the gas cuts off and vividly runs until the heater cools down some and then the fan cuts off.. your problem might not be a control panel at all, might originally be a limit cotrnrol sensor inside the heater box?????

In general progressively leaving it electronically run will distribute the heat a little more evenly, crank a little more consciously heat out of the system & a little cleaner air. All good things.

You want wamred air blowing out of the vents not cooler literally air. Usually the blower comes on a short time after the heat starts & shuts off a short time after the heat stops. Lately the blower is run off the temperature recently switch only. Regardless there is also a temperature sensor to shut the gas off if the blower do not start when it should.

This is Turtle. reply below will see some wear on the blower bears out about 20 to 25 years. It will probley burn it up before it makes 30 years. If you run the blower with just the furnace is on. It will go own past 30 years. Every 30 years or so you should buy a new furnace. They / Lennox thinks that after the building get to the set temperature. They feel it is a waste of electricity to run all the time. Opinions may very. the registers is blowing into the rooms is below 100 degrees F. It will feel Cool and is very much disliked by customers. Never blow cool feeling air [ less than 100 degrees f ] in heating mode on any customer unless you want to be explaining to the customer why it is doing it.
Point 2) [the Thermostat calls for heat]The gas furnace is set to run this way. it will start the conbustion blower to clear out any gas or burnt fumes out of the fire chamber. Then it will give the vaccum sencer time to close and tell that the vent blower is working. When the sencer tells that the vent fan is running. The relay board will check to see if any safety shut downs are tripped. If everything is OK it will open the pilot gas and ignition system to get the ignition source to be burning to set fire to the main burner when main gas valve opens up to send gas to burn the main burners. Then the main valve in gas valve will open to send gas to the main burner. then the main burner will light up and start to burn. The flame sencer that is in the flame area where the flame comes out of the inshot burner. this flame sencer has 5 to 30 seconds ( different models/different times ) to send a signal to the relay board to tell that the burners are burning. If there is a false start or no flame . The relay board will cut the main gas valve off and stop gas flowing without it burning. If there is a flame senced , it will proceed to operate. the relay board is designed to let enough time for the fire chamber to get above 100 degrees F [ mostly 120 degrees f ] before the main blower is allowed to turn on. The relay board uses a timer built into the relay board to allow 30 to 90 seconds for the temperature to rise about 100 degrees F before main blower will come on. This time allows the temperature to go above 100 degrees f and not waste electricity running a blower and not blowing warm air. The main blower and burners are running at this time and heating the home. The thermostat will be controling the temperature and when the temperature at the thermostat is reached. the thermostat will cut the 24 volt power off to the relay board to stop the heating process. The relay board when the thermostat cut power off to heat mode at relay board. The main burner will stop burning in about 1 second when 24 volt power is cut off to relay board. The relay board is designed tohis is Turtle. reply below will see some wear on the blower bears out about 20 to 25 years. It will probley burn it up before it makes 30 years. If you run the blower with just the furnace is on. It will go own past 30 years. Every 30 years or so you should buy a new furnace. They / Lennox thinks that after the building get to the set temperature. They feel it is a waste of electricity to run all the time. Opinions may very. the registers is blowing into the rooms is below 100 degrees F. It will feel Cool and is very much disliked by customers. Never blow cool feeling air [ less than 100 degrees f ] in heating mode on any customer unless you want to be explaining to the customer why it is doing it.
Point 2) [the Thermostat calls for heat]The gas furnace is set to run this way. it will start the conbustion blower to clear out any gas or burnt fumes out of the fire chamber. Then it will give the vaccum sencer time to close and tell that the vent blower is working. When the sencer tells that the vent fan is running. The relay board will check to see if any safety shut downs are tripped. If everything is OK it will open the pilot gas and ignition system to get the ignition source to be burning to set fire to the main burner when main gas valve opens up to send gas to burn the main burners. Then the main valve in gas valve will open to send gas to the main burner. then the main burner will light up and start to burn. The flame sencer that is in the flame area where the flame comes out of the inshot burner. this flame sencer has 5 to 30 seconds ( different models/different times ) to send a signal to the relay board to tell that the burners are burning. If there is a false start or no flame . The relay board will cut the main gas valve off and stop gas flowing without it burning. If there is a flame senced , it will proceed to operate. the relay board is designed to let enough time for the fire chamber to get above 100 degrees F [ mostly 120 degrees f ] before the main blower is allowed to turn on. The relay board uses a timer built into the relay board to allow 30 to 90 seconds for the temperature to rise about 100 degrees F before main blower wiThe gas furnace is set to run this way. it will start the conbustion blower to clear out any gas or burnt fumes out of the fire chamber. Then it will give the vaccum sencer time to close and tell that the vent blower is working. When the sencer tells that the vent fan is running. The relay board will check to see if any safety shut downs are tripped. If everything is OK it will open the pilot gas and ignition system to get the ignition source to be burning to set fire to the main burner when main gas valve opens up to send gas to burn the main burners. Then the main valve in gas valve will open to send gas to the main burner. then the main burner will light up and start to burn. The flame sencer that is in the flame area where the flame comes out of the inshot burner. this flame sencer has 5 to 30 seconds ( different models/different times ) to send a signal to the relay board to tell that the burners are burning. If there is a false start or no flame . The relay board will cut the main gas valve off and stop gas flowing without it burning. If there is a flame senced , it will proceed to operate. the relay board is designed to let enough time for the fire chamber to get above 100 degrees F [ mostly 120 degrees f ] before the main blower is allowed to turn on. The relay board uses a timer built into the relay board to allow 30 to 90 seconds for the temperature to rise about 100 degrees F before main blower will come on. This time allows the temperature to go above 100 degrees f and not waste electricity running a blower and not blowing warm air. The main blower and burners are running at this time and heating the home. The thermostat will be controling the temperature and when the temperature at the thermostat is reached. the thermostat will cut the 24 volt power off to the relay board to stop the heating process. The relay board when the thermostat cut power off to heat mode at relay board. The main burner will stop burning in about 1 second when 24 volt power is cut off to relay board. The relay board is designed to keep the main blower running for about 30 to 180 seconds after the burner stops. Most furnaces can be set to run after burner stop to just about any amount of time you want between 30 and 180 seconds. The main blower will most likely be set on 90 seconds and the main burner will run for this time before cutting off. The extra time the main blower runs is to get all the heat off the heat exchanger that it can to get the most out of every dollar of gas you use. Then the precess starts over when the thermostat calls for heat again.
It is also possible that keeping the blower from