Dissidia Final Fantasy: Opera Omnia is one of the finest, funnest, most generous Gatcha games I've ever played, to the point that I have spent money on it not for material reward, but because I felt bad not paying the developers for making a game I've enjoyed for so long.
Lot's of classic final fantasy characters, they interact believably and many storylines and moments in the game's story are legitimately compelling, a strategic and interesting battle system, many opportunities to pity for high class equipment, all characters come freely with events, story or permenant content, premium resources are given out like candy, the hard content is legitimately challenging and ask you to work on team composition to find interesting solutions to boss mechanics, nearly every character has unique stuff that makes them useful for many different situations... it's amazing.
The developers constantly interact with the players through community streams and responses to feedback, the community itself is vibrant and helpful, from the TCC podcast going over content to the Tonberry Troupe posting profession and helpful infographics for different upcoming characters, to the amazing database for the game run by Rem called "Dissidia Database," for researching upcoming events and looking up info on nearly anything in the game.
Let me repeat, DFFOO is an amazing Mobile Gatcha game, one I'm proud to be a part of the community of, and I highly reccomend giving it a try.
If you do decide to give it a shot, right now is a relatively good time to try it. We have a raid going on, so everyone contribuitng to it gains rewards for everyone else collectively, so in a few days you'll be swimming in starting resources! Not to mention two useful characters have a Banner right now, Kuja (FFIX) is very good against multiple enemies and can help sweep easy or repeatable content quickly, and Lilisette (FFXI) is a very potent buffer and debuff, and specializes in making bosses much less problematic by reducing their damage and turn potential.
Try to shoot for these two's EX weapon, and you'll find them useful for a long time!
Plus, Ultimecia (FFVIII) is Also on banner with Squall (FFVIII), and she is SUPER meta for basically forever, and is a very good investment, basically reroll worthy in every way. You probably won't have to reroll with all the gems you'll get playing the content, but you can!