Because his kekkei genkai isn't elemental based. Who would his barrier boost (aside from himself) and why?

And if it only affect himself, not much of a barrier is it?

That said, it could be the very first barrier that affect the enemy, hindering the enemy instead of helping allies. Something like lower init (since it's hard to move around) or whatever maybe?

But the first of anything tend to be a bit hard to make.