Unlike most exchanges, Coinbase is insured (). There is also some risk (I would think) of not getting your money in the case of a major hack, despite the insurance
There are still risks
- Your computer is hacked and Coinbase password is stolen
- Coinbase company goes bankrupt
- FBI or other enforcement agency confiscates coins
- Your computer or cell phone is stolen while you are logged in and thieves then steal your coins
Presumably, this is small, but who knows.
If you do use Coinbase, I would be sure to turn on as much 2FA as possible. For instance, you should enable second-factor authentication with an app like Google Authenticator. An alternative is to use SMS for authentication, but this surprisingly turns out to be very unwise. ().
If you have a lot of holdings, you might also look into a Coinbase Vault ().
The Nano is simple to use, holds a variety of currencies, and is inexpensive. Personally, I consider this method to be less stressful, though I would be comfortable storing large holdings on Coinbase as well (if I had any). I would not consider storing much currency on any site other than Coinbase.
You have two options