I am super ban and I don't mind because I wouldn't pay for online gaming .If you were to play offline an illegally downloaded copy of smash, and bought the game on release and played it online, would you be under risk of getting banned? Additionally, the save from the pirated version wouldn't persist onto the real one, correct?
But if you , better stay safe and don't play any roms even if it a copy of the originals you have .
On the other hand if you can buy a second switch for all the roms homebrew and leaked games you want to enjoy earlier .