MEW Cold Storage

Hi, I'v created a new paper wallet using myetherwallet. During the creation, it clearly states "You will need this password + your private key to unlock your wallet".

But from initial observations, it seems like the paper wallet private key is not encrypted, and can be used as is.

To avoid any fatal errors, can someone explain when is the private key encrypted and when it's plain text? Is the Keystore encrypted but paper wallet not?

Thanks!