Of course, it wouldn’t be a lootbox without some element of randomness, so you’ll never be sure of exactly what you get within a given crate. There are four different gem packages available, each one retailing for a different amount from merchants, so you could luck out and get a lot of money or wind up with very little money on a whole. But probably not, as player trial runs have shown it’s a bad bet.
So yes, it’s a lootbox selling in-game money. That’s a thing now.