You keep relying on the Chuck E. Cheese anology, but it simply doesn't work. At Chuck E. Cheese the prizes are a bunch of toys that your parents could otherwise buy, and the fun is in playing the games themselves which pay out tickets toward earning those prizes. That is in no way the equivalent of gamble boxes in video games.

Gamble boxes contain prizes that can't be bought outside the game, and in nearly every case contain prizes that can't be bought with the "consolation prize" (i.e. "tickets") that are dropped when you otherwise win nothing or very little compared to the actual prizes. And there is no inherent "fun" in clicking an "UNLOCK BOX" button compared to actually... playing a game in order to earn prizes. Not comparable at all, really.

If you're going to try to convince people they're not gambling (and you have quite the uphill battle to fight), you're better off likening them to blind bag grab-packs of card games / collector cards / toys, etc. - Pokemon, Magic the Gathering, sports cards, blind-bag toys etc. That is their closest real-world equivalent. Many would argue that those are also a form of gambling, as well.