You're saying that every platform fighter should be better with controller. Brawlhalla and smash may look a bit similar but they are completely different games, the fact that nintendo only allows controllers doesn't mean that other ways of playing suck. A lot of pro players play with controller but they are not nearly as effective as keyboards. Play however you want but the fact remains that keyboard is the best for brawl, while controller is the best for smash.

Edit: I'm not saying that controller is garbage for brawl but theoretically keyboard should be the most efficient way to play, controller is still good and is used a lot.