Nobody understands gambling, especially in video games

What is gambling? Strategic deck-builders like Luck Be A Landlord and Balatro have both been hit with high age-ratings by app stores and ratings boards, because the games are associated with gambling. Both are one-time purchases with no microtransactions, and no ties to gambling other than visuals borrwed from the casino world: slot machines and poker hands, respectively. Meanwhile, loot boxes and gacha games, which actually do have exploitative mechanics, seem to slide by ratings boards without much trouble. So what, actually, is gambling? And how do we talk about it in 2025, when gambling is everywhere?