I bet normally, I do not see any issue bitcoin price increase is given at all, I have a percwntage price i bet with, I convert the dollar to btc first before making betting.
I have seen the same, people are complaining that the fees are too high and it is taking a very long time to get a confirmation and without it they cannot gamble at all, while some may not consider this to be a problem if you are looking to make a transaction with a low amount of bitcoin it is entirely possible the transaction cost is going to be bigger or at least be a significant part of the value you are trying to send in which case it does not make a lot of sense to send that money over to the casino.
You are right, the transaction cost is another issue, but, as of recent, paying $2 to $3 worth of bitcoin as fee is not bad at all to transfer $100, this is the range of low transfer fee for now, within 2 to 3 hours, the transactions will be confirmed. But, if the people not satisfied with that, they can make use of altcoins like litecoin as payment.