I've been playing this game since it started (EN server) and i really love everything about it.
I'm a F2P player that never expended any real life currency on gacha games and, to this day i have every song currently available and at least 1 4☆ copy of every character on the game (except the newer ones).
Yes, the fact that is a gacha would be one of the main reasons of why some people don't even try to play the game
But i can assure you that if all you want is a fun rhythm game you should try this one