this is my personal opinion.. Withdrawal fees are the main factor, I have tried comparing the number of withdrawal fees between Bitcoin, Doge, and Ethereum on a gambling site, the result is the highest Bitcoin withdrawal fee (among the cryptocurrencies I mentioned).  I personally prefer to trade (deposit or withdraw) on a gambling site with Bitcoin (because I'm used to it and the majority of gambling sites provide Bitcoin and don't have a problem with withdrawal fees), but for some people, withdrawal fees may be a major factor for them to decide on where they play..