Breece Hall has had 11 games of 50 yards or less rushing, 8 of which were less than 30 yards, and 5 of which were less than 20 yards. I'm not saying that's necessarily Breece Hall fault, but lets not act like he's had consistently strong year. He's really just had 4 strong games.as a runner.
That's not so say Cook would have done any better had he been given the same opportunity, but we don't really know. I don't think he is as good as Hall at this point, but he wouldn't have to be to give a boost to the depth on other teams in the NFL. 67 rushing attempts spread over 16 games isn't really much of a sample size to judge from.