To be honest, I'm generally pretty bad at fighting games, but the touch screen instant attacks really do make things a lot easier. I come from old-school Street Fighter days (before any of this Cammy/T-Hawk/Dee Jay/Fei Long crap) and we simply didn't have the super punishing moves that the new games do. As I struggle to catch up, being able to simply tap a button with my thumb helps balance things out a lot when you move into the higher difficulty chains.
Even if you're not great at fighting games, it's a pretty beautiful looking game, and it was one of the cheapest at launch (besides Puzzle Bobble 3D). I won't fight you on Pilotwings, but Street Fighter is pretty worthwhile.