[musicale]

I don't think you're necessarily wrong, but I see gacha games as exactly what it says on the tin: capsule machines, which resemble slot machines for kids (and adults).

Of course real capsule machines sell you an actual physical item of some sort, and their bins are of limited size. Traditionally they also require physical coins. Physical items can also be traded (or resold in secondary markets) - which enables the "trading" part of "trading card games" like Magic or Pokémon.