Then ban all the other rare weapons. Its not feasible to allow a card into the deckbuilding and then tell people not to use it even though i can be used.
This sets up a precedent to lets say, allow fractal in a tournament but only on creatures at a cost of 4 and higher. Or only allow rage potions on your own creatures.
This is the only reason why the use of comboes have never been done before. Its simply a lot of confusion.
Other TO's and staff have made this argument far better than I do now.