"Overpowered" .... sometimes it's just used to say something is undefeatable.. E.g. Perf chance kills all players who play it.. Therefore it's too powerful..
But as v v v states. It actually reduces your score (unless it prevents you from getting lots of misses!)
Alicia Jewel wrote in Re: Share Audition ss's:It means over-powered. And actually, Perfect Chance reduces your score (at least in 8K, haven't figured out if it does on 4K or not), so you can't really call it OP.
Also, just to stay on topic, enjoy a very pervy line from Story Mode:

LOL that is an awesome line.