Equipment also feels like a response to modified brawl games. Specifically brawl minus and brawl +.
It allows you to alter character power/speed so you can craft your own custom version of smash if you don't like it. It'll never be used competitively, but if you feel the game is too slow or certain characters are too weak, you have the power to fix that when playing at home w/ friends. I just wonder how it'll play out, if people will actually use any of it or if people will just revert to playing w/ customization off (in the same way that most people don't play special brawl).
The Smash Community isn't like Smogon which tries to balance their metagame, they only ban stuff if they deem it too detrimental to the game but for the most part play the game as the top level dictates.
They'll most likely accept customizable moves but won't use them to balance the game, they'll just let people choose whatever moves they like. Best sets will be acknowledged and understood but people will be allowed to deviate from the "best build" if they want to attempt to utilize an unconventional setup an opponent may not be comfortable playing against.
I can't see anything that changes numerical stats being considered though. Just too much trouble and having characters without augmented stats is much easier than trying to get everybody at maxed stats or whatever is completely optimal.
Yeah, i'm really hopeful that equipment is banned at the competitive level but custom moves are not (at least for some tournaments). This will make it so that characters that people normally consider to be bad or mediocre might have a fighting chance against 'good' ones if the custom moves are set up just right.
The MAIN reason i can see them being banned though is counterpicking movesets and how long it takes to change them (like, do you have to go into a separate menu or can it be done from the character select screen). If it takes too long to change custom moves (oh, you're playing marth, well i'll do mario w/ ABCD custom moves... oh you're doing Mario with ABCD, well, i'll change my marth to be WXYZ moveset, etc etc etc etc), then it won't be allowed.