Internal exchange feature will become issue for the casino side because the allegations will rise against them for money laundering so why they have to take such risks. The fees are higher than the actual transaction fee but this is not only happening in Roobet is my statement. In future the fee structure may be redesign if the casino feel its necessary but so far so good so I don't expect them to do.
I am not so sure. I mean after all exchanges manage to work with what they got and casinos could end up building one inside as well. I understand that it is extra work and it becomes very difficult legally speaking, however it is not something that can't be done neither. Just remove every single stablecoin or fiat that could be used, in that case it is only crypto to crypto exchange, even stable coins are just crypto but stable, however that could be a legal problem if nothing else, so removing them leaves only crypto.
So, let's assume you are a casino and only allow btc, eth, bnb, ada, ltc, doge and nothing else, and do you believe an exchange that allows you to move money between them would be hard? You could let people trade between each other without casino getting too involved and even in that sense people would find the right price eventually due to arbitrage chance. I think it could be done as long as it is not legally a problem.