I think most backs get more than 5% of their yards on 5% of their carries. I don't think most good backs get 40% of their yards on 5% of their carries.
As to my hyperbole, the stat merely reiterates what I've argued to death about CJ Spiller. He is the definition of inconsistent as a running back. Getting 40% of your yards on 3 carries is NOT good as an RB. It makes you a weapon to be used sparingly. He is unable to grind out any sort of significant positive yardage. And that doesn't even touch upon his inability to block any defender, his low football IQ and poor vision.
At the end of the day, he's a below average football player with great physical gifts. He will be unemployed or one of the worst RB's in the NFL when he loses a "step."