You can introduce more variety of card games where the user will play against another user. PvP games generally catch more attention as the chances of winning here are higher, so you need to focus on the UI and graphics of the casino to deliver top notch user experience. Regarding the games, then street dice and some variety of card games can work. Many Asian countries play card games in day-to-day life. So implementing those with cryptos and gambling can really be a masterstroke. Also, if possible, keep the house edge low; this will fetch more gamblers.