Bankroll is needed and its no brainer that a site should have because how you would pay out users or winners if you dont have money to pay on?
but they had mentioned that they are still on Beta phase then it might be the possible reason.
Bankroll depending on the type game you are play, if PVP game then doesn't need a bankroll since the player play against other player and casino just act as third service who provide a room for the player.
But since this game its not an PVP game and play against the banker/house, they should at least deposit some money into the bankroll. Otherwise, no body gonna to play on the casino because tired waiting the bankroll money.