As is the case with every game, but if you take hours to learn wavedashing and stupid glitches and exploits to make a game "competitive" then you're kinda taking the fun out of it.
Competitive players want to subtract from the game until there's nothing left but "competition". Can't use stages other than Final Destination or maybe Battlefield because they're "too large" or "too random". Can't use items because they're "too luck based". Can't use most of the characters because they're either "too broken" or "too shit".
Noncompetitive players want to add. New stages because they're fun. New items because they're fun. New characters because they're fun.
By making Smash competitive you take away what's unique about it and try to make it like a fighting game which it's not designed to be. It's a party game.