Actually it's not that evil. Genshin Impact made 1$ billion in 6 months because they use a super addictive gambling mechanic called gacha.

But the thing is that there is like a 1% of all players who spend 99% of the money. They call them whales.

Basically they spend $10,000 rerolling countless times to get some rare champion or whatever. Why? Because they can, or they're addicted, whatevs. But the point is that these people end up financing the game for the rest of us basically.