I’m not that familiar with CoinRoyale but I do gamble using DOGE and I think you should include this on the option that’s why I voted for DOGE.
Many gambling site started to introduce more deposit option and gamblers loving it, this should be the start of many crypto gambling site to start creating at least 5 deposit options plus the fiat currency.
I voted for Doge too! And I share the same opinion about deposit options, there should be more coins! Bitcoin and Ethereum are the most popular, but at the same time, they have the highest transaction fees... I guess many gambles with these two, but adding some coins with low transaction fees is good for the masses! Whenever I can I choose TRX, Doge, LTC, from recently BNB is great too!
It's not hard (and it can be good for your business) to check what the competition is doing... check how they attract players, and even more important how they keep those players in their casino!