-Do you have a separate wallet just for gambling?
Nope coinbase all the way
-Do you have a daily limit on your bankroll?
Nope, once I decide to gamble, I start with a small amount like 1 MBTC or something similar but in the end , get back to zero. Good thing I do cash out most of the BTC I make into USD
Why are you keeping all your Bitcoin in Coinbase? (that's what I understood by reading your post). I think it hasn't been said enough apparently, that you should never, never keep your main stack of Bitcoins outside anything that isnt:
a) A Bitcoin Core wallet with your wallet.dat encrypted and secured
b) A BIP38 encrypted paper wallet
c) A Trezor or other similar hardware wallets
Storing your main Bitcoin stack outside of those options is being pretty insane or just don't get understanding the risks yet.