Just how legit is using a controller to play MS?

I use a controller, and although I know about those things that you can do with it on MS, I don't do them. It's not the controller that's illegit, but the way that you use it. I can't think of any possible argument in favor of using a controller for any sort of auto-clicking feature, but I don't see anything wrong with using one to play the game.

I'm pretty sure that people who bot with their controllers don't really have any logic behind what they do.. lol