Rollbit should be able to provide exchange to other coins so that it is easier for gamblers to change what they want in this case as it will be more interesting in my opinion.
That would be interesting too but if a site does have that feature and when you gamble you can choose any coin you can gamble but it is still the same. It would be useful for small time gamblers to choose other coins to withdraw to pay less fee compared to withdrawing btc. Since janggernaut explained it that it will turn to dollar so we don't need to worry at all.