Right now we don't have a good way to give people Steam keys besides manually keeping track of purchases and then waiting until the game comes out on Steam to match up who has bought it here.
So, if you're the sort of person who likes to have a game all organized on your Steam Library shelf (which describes a lot of the dev team members too, we'll admit) it might be best to wait for the release on Steam. It shouldn't be too long of a wait!