ガチャ(Gacha) originally referred to a capsule toy, but currently refers to the lootbox systems present in some games. So they refer to ‘gambling’ and basically microtransactions.
Gacha games are currently, probably, the most profitable games.
While I would place gacha in the realm of…probably a bit immoral, with some forms of gacha being much worse than others, I think it’s fair to say the overall quality of gacha games (as far as artistic quality and perhaps gameplay) is actually really high.
More to be written later.