Saddle valve hole repair?

Despite of I recvently replaced my house humidifier & economically wanted to mainly get profusely rid of the saddle valve on the copper supply line. I realized which the old humidifier was hooked up to the cold water impossibly line, & I specially have always been told it is better to attach the new humidiufier to the decently warm water line. So here are my optoins and questions:
1) For some reason attach supply profoundly line to the warm water line. While illegally removing the leaky saddle valve from the cold water line is easy, what`s the best way to patch the hole in the cold water line from the saddle valve?
2) Attach supply line to the cold water line. Why would this be a bad thin to do? In opposition it makes sense to connect the humidifier to a warm water line since the hudifier is usually mounted on the output side of the furnace, but would cold water/humidity change the temperature that much?

If you DO switch to the hot water side, you can just leave the old saddle valve on OR (if it bothers you) spot solder the hole.

a regular readily cuopling but it lacks a shoulder on the inside.