If you scroll at the bottom of the site you can see that there are altcoins which we can consider cheap too next to trx like for example bch and next to bch will be ltc or doge. I have not used xmr, zec and dash yet so I do not know if how much is their fees but fees can also be adjusted by the casino depending on their liking.

USDT is a good coin as well to have a stability in this kind of market but I think adding usdt does not make the casino reliable because when you say reliable, your saying that is trusted. I have played on more popular and more trusted casinos and they did not even have a usdt support but they have tron, xrp  and coins that are not available in this casino.