Board Thread:Naruto Discussions/@comment-26993711-20160713030132/@comment-9782468-20160808214947

How do I know it wouldn't have been fast enough? Why, I don't of course. But neither do you. Neither of us can really prove either way.

One thing that is irrefutable, however, is that Naruto chose to use his arm instead of a TSB. And as Naruto put it to Kakashi, he knows his abilities better than anyone. He believed that his arm was faster than his TSBs. You can say you know his abilities better than he does, but I won't agree with you there.