It is a kick in the teeth to Indie developers though who submit good work to Valve only for them not to accept it onto the store.
Seems to be that if you license the Source engine, you are guaranteed a spot in the Steam store, albeit more of a placeholder.
Although at the moment, it cannot be purchased so maybe that is part of the terms when you license the engine. Obviously, it is Steamworks so the Dev/Publisher can distribute their own keys.