I don't think there is a need to set up an internal forum as they have an active chat specific for players of the games' interests the Telegram groups and channels are all enough for the players and the admins to interact and get all the latest updates.
They also reward the most active chatters in their chat they have 5 channels on Telegram and it serves the members' needs when it comes to communication.
I have no doubt About what you say, you really say what it is , but I say it Because in an Internal forum you have control of your community, how many there are and how many are Willing to defend your project, you know who are more loyal and they know that their Own Members are worthy of growing the community, a Strong Community when you tell them that they want more people in a casino they are capable of getting even their own families to play in a casino, Because I Myself have seen that "fever" that is given by a platform , of course it is an idea, but I Know that a Community from there you can get clear numbers with who is really Counted on.