Question: why do you guys think/believe that his weapon is useless for the IS-sport and meant for hurting people?

its a shield nullifying sword right?
he can pierce his enemy shield -> shield pierced means zero shieldpoints because a pierced shield is broken -> he is the winner with a single blow. (they never said that the sword "bypasses" the shield like a ghost-sword or something like that, at least not in Ayako's version)

his problem is that he has to get into close-range to make this attack work, which is why this sword is a all-in-weapon and *needs* to end everything with one or 2 blows.