I prefer Eth as it has a lower transaction fee compare to BTC and aside from that, I have also a local exchange that I trust that offers also a conversion from our local fiat into Eth so it is very simple for me to cashin via Eth and also to cashout if in case I will get lucky.

And XRP will be my second option if in case Eth is not available in the casino that I want to play but if both will not be available then I will look for a good casino that accepts either of the two as I am comfortable using the ETH or XRP rather than btc or BCH.