They "might" make profit from the interest as well, you are leaving your money in there and that is an incentive, and the more money stays there would mean they could use that for more profits, they could use it for something, could be mining, could be something else, I don't know how because if I did, I would offer the same and get people to invest to me, but I can't, hence I do not think that I can give you the answers but I think they could still profit from it.
Same goes for FUN tokens, they could offer more stuff, better HE, better interest rate whatever and they could still profit from it. All I wanted to say is that it could be a "loss" because there are costs for the casino, not that I believe it is a loss for them, it is definitely a profit, and I think you are right that they wouldn't do something that doesn't profit them, I just wanted to say it must be profiting them something.
You are correct that gambling sites or exchanges give investment pool, services to bring win-win situations for their companies and customers. Customers must know what they are doing with their money: choose a good company with high trust and good reputation to use, to store money, to invest.
FreeBitco.in is a trusted gambling site and it has been in the online gambling industry for many years, almost 1 decade: since October 2013.
Customers have to have own investment schedule and have a saving or preventive capital for urgent use in lives. I never recommend anyone to use all life saving or make big loan to invest in crypto or in anything. It is gamble with their lives.
FunFair token:
https://coinmarketcap.com/currencies/funfair/markets/