I'd say that at this point, because he's the only one, it's hard to say that there is an advantage. Seeing that there are many double amputation who run with artificial limbs, and he's the only one who has made it this far, it's hard to see this as an advantage. Now, if there are like 10 of these guys at the next Olympics, then it would seem like this is an advantage. And what happens if a runner without an amputation uses this?
So at this point we really don't know.