"Worth"? Your time, yes. Spending money? Maybe a little if you REALLY enjoy it.
I played the whole game FTP and have three 5-star characters just from in-game gacha points, and they're all I need. Even a lot of the 4-star characters are fun to play.
I think if you like an open world game yes the world i pretty inmmersive nd has a cool gameplay expirience i second the guy above me you dont really need to spend money a friend of mine describe the game as Pay to skip and i think is right, like you could get the characters you want eventually but if pay you would get all in a short period