There's no max bet limit atm.
That's bad. What if someone puts 30 Bitcoin on 0 and wins? You need to be able to pay any amount that someone can win. At most casinos, the max bet is such that a user can only win around 1% of the bankroll at a time.
At the Star Casino on the Gold Coast & Brisbane they have electronic roulette where you can make a $30,000 bet on a single spin and I've often wondered what would they do if the roll (as LoyceV says) came up on E.G. Zero $1,080,000 AUD (Close enough to a Million I guess (which would mean they'd need $100M to cover a 1% bankroll as described above))
So what LoyceV is saying is that you'd need to have a Billion Dollars in BitCoin to payout a
BTC 30.0 bet on a single number.