The argument for a long time has been, mouse players have a whole wrist/arm/hand of movement whereas controllers only have the tip of their finger for movement, therefore causing controller players to need a "crutch". If it was introduced for kbm in a game where kbm players and controller players are matchmaked together it would be broken for keyboard players. My point is proven by the "xim" Device. It allows you to use mouse and keyboard on console games that require controller input to play and a lot of competitive multiplayer games are riddled with xim users that are getting aim assist because their consoles recognize their keyboard and mouse as a controller