I play this to farm Nintendo silver coins when I need the limited-time avatars. Beside that it's a masked New Super Mario Bros. limited behind a pay-wall with some challenging mode that will make you play against some ghosts.

The main game is very short and not really worth all that money at all. Half of it and you may consider it only if you're hardcore Mario fans.

Strangely enough I don't think it can be considered a gacha. But surely a live service phone game, so we are not much far away.