Bitcoin performs well in gambling, it always been,maybe I'm already used to it and haven't tried to do bets on other alts. But no matter what coins or alts it is when we bet we usually convert it to our own fiat or calculate it in our mind. Any can be used as long as were comfortable on it and we see more potential on it to win.
The reason bitcoin performs well at the moment is its ease of use and the anonymity factor since people don't like to gamble with real money and then have an eye on the profits from the government.
Anonymity I would say is the biggest reason. But it isn't going to be that way forever.