Predatory as in they literally employ psychologists to help design them to be as addictive as they can be, then they market it towards kids or at the very least don't really do anything to prevent kids from gambling in them (yeah it's also partially a parenting issue but can't really expect all parents to be tech savvy enough to understand all everything about gaming).

Then there's the other sucky, but just not sucky enough for it to be an illegal side of things: games that these mechanics suck ass and we are getting less and less objectively good games because more and more games seek to make some quick buck by making their games casinos of sorts.

It's only as luxurious as being addicted to cocaine in hopes that the next line will hit like the first one, or in game terms, hoping that the next loot box gets you the skin/character/whatever you wanted and releases that quick dopamine rush. Rinse and repeat.