I was honestly surprised that online fantasy sports games were allowed to run without interference for as long as they did.
They were until they got greedy and turned them into what amounted to directly gambling on the games themselves. This was the period where they were running wall to wall ads on ESPN and any other sports programming you could watch. Legislatures woke up from their coma and a lot of them closed the fantasy football loophole or declared them games of chance instead of skill, a distinction that matters for what is considered "illegal gambling" in many jurisdictions.
Actual fantasy leagues are still legal in many places, but disguised sportsbooks like fanduel and draftkings are in pretty big trouble, especially after being shut down in New York earlier this month after fairly lengthy deliberations.
I think gacha game makers may actually be surprised that they can make as much from degenerate gamblers without even letting them actually win anything. They have to be careful to make the "winnings" nontransferable because if they didn't, there'd be an economy where people would try to buy them directly, making them once again a gambling game.
It seems perverse, though, that something as destructive and addictive as actual gambling can be allowed to exist where gambling isn't because it's completely destructive instead of just partly destructive with at least a chance of winning something.
(My personal opinion is the state should step aside and let people choose their poison as they will. But it's still perverse to allow this gacha shit in places where, for instance, slot machines are illegal.)