No, it's not bad for the hard drive, and usually doesn't make more work for anything. usually, the only thing you need the CD for is to boot the game and once the game is booted you can take it out so it shouldn't cause any more stress on the system.
thats true, and the fact that it installs it on the hhd is for performance reasons. alot of the data that is on the cd is crunched , so when it's installed on the hhd the data is unpacked therefore stretching out the data on the hhd makes for faster loading in scroll type games and helps with graphics.
Yeah, I do personally find it very annoying that I have to keep putting discs in for games that only read it when you click the EXE, and never read it again, and it means risking scratching the disc everytime you do this.