I believe you can pay off your room charges with cash at the front desk- the front desk is the only place they take cash besides tipping housekeeping, valets, etc... you just can’t pay for your dinner or souvenirs with cash at the restaurants or store. So you would have to charge to your room and then pay it off with cash as opposed to paying with cash when you eat/purchase. Or get a gift card from the front desk with your cash.