Some do, people like to try for achievements the good old fashioned way.
Instead of the false feeling of achievement when people use the other route.
Basically what I am saying is, you may not want achievements or care about them, that doesn't mean everyone else shares your view.
I completely agree. Some folks care others don't. So the option would be to set it up so that the mods if activated do nothing to your score. There are ways to make that happen. I was just saying that once I finished the game I had a blast going through and playing around in God mode. Maybe Im a little touched in the head but ... well its fun!!