I'm ngl, I clicked the casino once, it said maybe later and I promptly pretty much forgot it existed. The coin requirement was just high enough to interrupt flow but not high enough I ever felt the need to gamble, considering the potential to lose and thus spend more time coin grinding. Maybe consider some sort of item or reward in the gamble hall, maybe that changes things later, rather than just "maybe make grind less, maybe make grind more." Would also give more of a purpose to the coins, rather than just to slow down the story. Just the ramblings of a random internet man, no need to take it as gold.