i don't think it has anything with believing in the future of their token because the creators of these tokens know better than you and i that their token is useless and worthless.

the only reason why they pay in their own token is because it doesn't cost them anything! if they wanted to pay in bitcoin for example they would have to spend money and buy bitcoin and then pay people. but when they pay in their own token, all they have to do is just create them out of thin air with no effort or cost!