If gambling is a completely separate project, what are the advantages over existing and reputable projects? This is unknown. If gambling is built into the Meta, then this will entail strict regulation for the entire Meta (even the ban of online access in some states), so I do not think that this will happen, since the losses from this will be greater than the profits.
Some people will prefer the regulated casinos over the unregulated ones because they'll think that if something goes wrong, the department of justice will make it right eventually. You can't do that kind of stuff with the unregulated casinos. They may just take away your money and show you the door. Sure, they'll lose reputation but that didn't stop 1xbit, as you see they are still up and running.
Do you mean the Russian scam project 1xbet (and all its numerous clones)? In fact, I wonder how it is still alive - it has an extremely negative reputation who has ever come across him, but massive aggressive advertising is apparently capable of attracting many new users, so they continue their activities.
It would be interesting for me to look at Meta's gambling project only in one sense - I see that there are players who turn out to be in the black, for example, when sport betting, and I would like to know how Meta will fight with such pros who will beat them.