[sillysaurus3]

It's insanely different from having your money in banks. A bank is backed by the government. If a bank goes under, you still get your money. If Coinbase goes under, you get nothing or very little.

Funds from Coinbase should be evacuated to your own secure cold storage wallet immediately after you purchase them. You should never hold a balance higher than 0BTC for any length of time on Coinbase. Follow this advice and you'll have your money forever. Don't follow it and you'll lose your money the moment Coinbase suffers any serious theft, a technical disaster, a rogue employee, or the founder steals coins.

(I speak from experience, having lost a massive amount of money when Mt. Gox went under for one of the above reasons, which I probably won't get back.)