[arsenal]

You don't need a leash... The leash is there from begning of snowboarding. It straps to your binding, which in turn straps to your boot.
I have no idea what it's intentional function was but I am guessing it's there to keep the board from taking off on you while you are not strapped into your board.
Well, if you have tried walking with your feet out of the bindings, with your board leashed to you.. it is not easy nor fun. Just learn to "skate" with your lead foot strapped in.

The only thing I can think of when a leash would be usefull is if your binding straps break. That would keep your board attached to you. But both straps would have to fail at the same time.. on both bindings..

yah.. it's usless..