Cheating does not ruin games at all, the point of a game is to entertain you, just like books and movies. If you happen to be purely enjoyed by reading the last few chapters or skipping parts in movies, you can. It's purely up to you, whether or not cheating actually ruins games depends on whether or not you like cheating.
It's like figuring out you can build a sand castle faster by doing some special quick/easy way, and the only reason you like doing that is so you can tear it down over and over again because that's what entertains you. Then you get these pissy-sandcastle-elite starfishs who are like "What the hell are you doing!? That's just ruining the magic of sandcastles!"