Yeah, the lack of microtransactions and theme are its strong points. It even has some light story stuff.
But if you want to play a game of that style, you might be better off playing Star Rail(from the dev that made Genshin Impact), which is a f2p game with tons of microtransactions but you can really enjoy it without spending a dime. And Star Rail’s design and production values are unrivaled.
I havent played the game but from what i understand it seems like your typical mobile gacha game, where you collect characters and they autofight enemies. Except it isnt f2p and doesnt have any microtransactions. It is just a paid game, with all the trappings, design and progression of a f2p mobile game.