I don't play them offline either. Only fighting games I own are SSB Melee and Brawl, because they are simple enough and filled with Nintendo fanboy stuff which I grew up being and sadly still am to a small extent despite little reason these days.
I played online a few times. It was okay. I think I was using Ganon, Sheik, or Zero Suit Samus mostly. I know they banned Meta Knight from tournament play lol.
I suck at fighting games, against the pc or other player equally at times. Its like the one genre that I just never got any better at. I'm pretty bad at FPS but I still get the occasional kill streak of 3 or 4. Under ideal situations (i.e. my team not spawn camping the other team) I am a fairly decent sniper. I mainly suck at those moments where you suddenly come face to face with someone and they instantly head shot you despite having no way to have know you would be right there. Or as is the case in most games, when they have some kind of OP power active that makes them a badass temporarily or they are abusing some OP weapon set up or glitch that overwhelms every other method of play.
Anyone remember Killzone 2 multi, and how before it was patched everyone would just run around with the heavy armor and the magnum one/two shotting people? Or spamming rockets everywhere? At least in that game you could disable certain weapons, and so rockets were pretty much banned from all matches. Then it became everyone spamming spot and mark, which killed my sniper career pretty effectively (because stupidly it worked even on fully cloaked snipers with a really short CD) and made positioning/flanking in general completely pointless.
That's how playing a fighting games feels to me. Completely pointless because I haven't spent years mastering every conceivable playstyle and the way to counter it, and perfected every archaic button combo to perform all the best moves and counters and reversals etc.
It may as well be a game that requires me to play the shamisen while evading a shark, and then doing it online against thousands of other people that have been doing it for 12+years lol.
Also I can't think of a genre that is more prone to imbalance and outright cheating. When one player can break half the rules of the game, why would you keep playing that game?