We are not aware of such options. When you top up your account with XRP, you will have access to the entire gaming range of a casino website. And the funds for spinning the reels or bets will always be pulled from the main account, and, if necessary, converted into the main game currency.
However, you may come across games that only use cryptocurrencies. This is due to the fact that the markets for traditional currencies and new digital currencies still operate separately.