I explain my recent experience with paper wallet. This might be helpful.
I generated a paper wallet from coinbase and securely stored its private key in cloud. I also used blockchain.info to monitor the balance using the public key only (no private key is entered). And recently, I wanted to transfer few bitcoins from it to sell. I knew that if I import the private key in coinbase.com, it sweeps all the coins from that address and transfers all of them to a new address whose private key is managed by coinbase. Blockchain allows to import private key without sweep, but I did not want third parties to learn about my private key. So I thought of using Multibit client. I installed multibit client, exported all its private keys to a file, and added my private key to the end of the file and imported back. I see all my coins in multibit (1.6 BTC). So far good. Now I transferred, 0.5BTC to coinbase to sell them and multibit showed the balance as 1.1BTC, which is correct. But the watch only address in the blockchain started showing only 0.6. I got confused as the balance I expected was 1.1. So I carefully monitored the transaction and found that 0.5BTC was sent to my coinbase address and another 0.5 was sent to one more address which I didn't recognize. As multibit was still showing the correct balance I guessed that it might be one of the multibit address and I actually found it there. So, multibit actually took coins from my paper wallet address and put it in an address that was generated by multibit, which I did not expect. I was planning to use multibit only as a temporary solution and was planning to uninstall it after I transfer my BTC to coinbase. If I was not careful then I would have uninstalled multibit and deleted the wallet. Now I learnt how multibit works now, and I am not sure why it does like that. But a lesson learnt.