Handing all your Bitcoins over to an online wallet is still risky business. Unlike banks, they have no insurance. If someone runs off with all the money, it's gone. And due to the anonymous nature of Bitcoin, it'd be almost impossible to find the culprit, if done correctly.

If the balance on my online banking is incorrect, I calmly ring customer service, knowing they'll fix it. With CoinBase I'd react completely differently. With the amount of other Bitcoin services that have been hacked in the past, I'd be scared CoinBase had met the same fate.