Yes, can't argue that it helped in the early-ish days (though one could argue, if more transactions means more adoption per se). But nowadays gambling isn't helping a lot with adoption I think. Yes, lots of people are gambling with crypto nowadays, but this scene is kind of a closed circle, i.e. someone who was gambling with fiat in the past is now maybe gambling more with crypto. But outside of this circle it doesn't help with adoption, because people always lose all their crypto while gambling, so it's one way traffic to the operators, who get this "money". The operators probably sell parts of those profits for fiat and who buys it again ? The gamblers

You just don't get new people into crypto because it's now possible to gamble with it. If someone starts gambling now, he does it because of very personal reasons and not because he thinks: "Oh cool, I can gamble with crypto now, which is a great benefit for me." And tbh - at least for betting - the crypto casinos don't offer anything special; most of the time they are worse all in all than the big traditional fiat bookies. With gaming things are or will be different.