I feel sorry for people who are addicted to gacha. It's one thing to like it in a fictional setting, but really expecting to win something in real life, when the odds are stacked against you, that's just escapism-level wishful thinking.
And for dessert, the generic Japanese pudding. i.e. Pus-Jelly. Tastes vile. But everyone in isekai series seem to love it.
Anyhow, it seems they'd get the most DP by renting out the dungeon as a literal jail. Just buy criminals from various countries and lock them up permanently in there. Easy DP.