That doesn't seem like a large enough beta and it really only targets PC gamers. I would think that they would want to be trying to capture console gamer share rather than existing PC gamers.
Some of the biggest fiascos in gaming have come when company took its fans for granted while trying to expand into a new market (e.g. Ultima 8). The usual result is losing your existing base while not building a new one. Once Valve is sure that the PC gamers are on board, who should be their easiest sell, they'll start going after the console players.