It is possible. But I think they will be focusing on their own coin for now. After building a good reputation and established a good impact in the crypto community, then there is a possibility that they will include their coin in some gambling sites.
Some people might use it to gamble, it is inevitable.
If someone made a bet to his friends and he lost, it is obvious he will be paying his friend money. If he has Facebook coin then he can use it to pay his friends. It is not the gambling you think but that is the only way I can relate it to gambling since most of the sites that I read for some time now says they will only be in their sites.
Facebook, will be launching its own cryptocurrency for use in its messaging apps, Messenger, WhatsApp, and even Instagram.
https://cryptodaily.co.uk/2019/03/facebook-coin-what-we-know-so-farWe know it can't be transacted on gambling sites so I think it is impossible. Also, it is said to be connected to dollars so I think people will not be using it to gamble that much if it can be used.
