crowley used the metal tool in season 1 to start time, and we learn that he's used it first to start space. to create the stars -- he still remembers how. he still remembers all of heaven's passwords: in the books crowley is described as an optimist because he has the "utter surety... that the universe would look after him". not god, but the universe. and of course he does: he created it and he's looking after it, too.
think about it: aziraphale had a sword, but crowley is about to face satan who wants to destroy the world, and crowley's only weapon is a tool of creation