Cheating AI turns every game into a puzzle game. The game turns into figuring out what the weaknesses of the AI are and taking advantage of them at every step. That is the only way you can compete against the massive advantages cheating gives.

Typically there are some easy micro and macro tricks that make the AI do something very stupid. That's why kiting is so ubiquitous in games - the AI just keeps following you while you whittle it down. Doesn't really work against a real player if they're microing the units.