In other games, yes, in Overwatch it’s highly frowned upon but not bannable as of now.
They directly improve a player’s gameplay in vastly different ways. WoW isn’t a hard mechanics focused game, pressing buttons is easy, knowing which order to press them in is the actual challenge. An MMO mouse adds efficiency, but doesn’t skip the knowledge check. In Overwatch, aiming is the challenge, there’s a mechanical component that literally cannot be ignored. XIMs undermine that challenge by using hardware to artificially improve the mechanical skill of the person using it.
The question is, would you call an aimbot cheating? And if so why would XIM not also be when they do the exact same thing?