Could we also expect that facebook may have a feature where gambling (that uses crypto/ facebook coin) is allowed?
As far as I know, Facebook is a U.S. corporation. It means that they (Facebook) need to acquire gambling licenses to operate (in the U.S.). I think that gambling is not their business. Moreover, many countries ban gambling and would hurt their core business if they want to operate an online casino.
Furthermore, 3rd party casinos would think twice to add the Facebook coin, because of lack privacy.
So my answer is no.