I keep seeing people say that paper/brain wallets must be swept. As I understand it when you send an amount that isn't the full amount of an address it sends a "change" transaction that sends the remaining amount back to the address.
Can you not do this with paper wallets for some reason?
They don't have to be swept, but it's recommended that you sweep rather than import. Also, never import publicly known private keys:
https://bitcointalk.org/index.php?topic=216278.5