Cold storage allows you to store your encrypted wallet offline altogether. The public (sending) addresses can be used any time to send additional bitcoins to your wallet, but spending the bitcoins would require physical access (in addition to knowledge of the password). Cold storage should be used for holding large amounts of bitcoins or other cryptocurrencies. Some of the great cold storage devices designed to safely store your coins are:
This is my opinion based on my research. I am not a financial adviser and always encourage people to do their own independent research before investing.