The problem with Blockchain/any online service is that if you somehow get your details stolen (ie from a keylogger/reusing passwords/not having 2FA enabled) they can quite easily log into the wallet there and steal everything. The only way around that would be to create the paper wallet and then delete the private key from the wallet.

I personally don't like paper wallets as a cold storage solution - sure they are pretty safe (please encrypt with BIP38 so if you lose one you don't have your coins stolen) but you can't actually make transactions without having to import the whole address again which is frustrating.