AfterStarX, cheats are optional because some people like to use them, and others don't. If you or I use them, we get bored quickly. If Lews or gridlock use them, they have fun.
You have to option to cheat at solitare (when playing with real cards). Does that bother you?
You can cheat a story and read the last page first. Does that bother you?
I agree that cheating in a game, or in life, where other people are involved is a bad idea. Everyone should play to the same rules. Battlenet has this problem. So do relationships. And taxation and social security. That's why there are stiff penalties for cheating here. But in your own world (ie. single player), it doesn't hurt anyone to cheat if you desire.