FFBE was fun for a summer a few years back. The gacha value was so shit that I never spent a dime on it. Had good sprite work and the perfect bright lights and flashing colors for dopamine.

If you really wanna gamble, Pokemon Go's great because you do have to gamble for the shinies but to do so takes enough time that you generally can get a good bang for your buck. Though they do obscure and hide odds which is horseshit.