I guess it's more common to use alts for gambling like EOS, LTC or ETH since the majority HODLs Bitcoin.
I dont think so because if we do try to observe on how many cryptocurrency gambling sites at the moment and trying to check on the best history you will surely able to see that most people do bet using bitcoin
there might be other coins as well but not really that much if we do compare it to bitcoin.I agree on what quidat say above when it comes to excitement where its different when you play using bitcoin and using
other altcoins.It isnt really that much important because people can choose on what they would use according to their own funds or coins owned.