There are many Smash players out there who feel that the GameCube’s controllers are better for playing the game. Of course these are personal preferences, but it is obvious that this is what a good many players feel. If you do have some lying around then you will be able to use them with the game just fine.
If you don’t, there are probably some you can find online on websites such as eBay. Alternatively we have recently heard that PowerA could be making officially licensed GameCube controllers for the Switch, so that could be worth checking out if you’d prefer owning a new controller versus one that’s second hand.
Super Smash Bros. Ultimate is set for a release on the 7th of December. It will be the latest installment in the franchise and as its name suggests, will be the “ultimate” version of the game as it essentially brings all the characters from the franchise into a single game.