Those two statements kind of don't jibe.  This guy (like many other forum plagiarists) is here to make money, plain and simple.  If you give him any kind of temporary signature ban, there's little chance he's just going to wait it out or to somehow improve his writing ability.  The main reason these idiots copy/paste other members' content is precisely because they lack writing skills--or they have nothing to say about a given topic but need to make a post anyway.

I'd only support signature bans if they were permanent, but since it's too easy to create new accounts I don't think it makes much of a difference unless the account is of a fairly high rank.  In OP's case a permanent signature ban would likely cause him to abandon his account, and he might have a hard time ranking back up to Full member.  Anyway, given that he's lying here in addition to his original offenses he ought to be permabanned.  IMO now isn't the time to lessen the consequences for stealing other people's words.