Wellllll in most driving games you accelerate and brake with the triggers though, and the left stick does nothing on the vertical axis :P
Okay for real though, I'm not here to tell anyone how to game. Use whatever feels right for you, and having the option to invert stick axes is a great inclusivity feature I'd never argue against! I just have a little too much fun arguing with people trying to rationalize something that really just doesn't need to be rationalized to be valid.
You might have to sign out and then in again. There was a bug with the initial release that caused this kind of behavior