I'll accept as fact that ICF sprint boats have bow and stern rocker. They certainly look that way from the pictures on the Nelo site.
However, one must not commit the logical fallacy called hasty generalization.
Premise: The fastest sprinter in the world, Hussein Bolt, has long arms.
Conclusion (fallacious): Longer arms make faster runners.
Premise: The fastest sprint boat in the world has rocker.
Conclusion (fallacious): Rocker makes faster boats.
The fastest sprint runner and the fastest sprint boat are what they are because of a combined package of characteristics, traits and specifications that work together in synergistic harmony. You can't, logically, just pick one characteristic or spec out of the specialized sprint package and make a sweeping conclusion about it, unless you have further facts to support the conclusion for other types of running or paddling.
It makes sense that when you have (a) made a canoe as narrow as possible, (b) for a high kneeling human body, (c) maximally swede form, (d) at maximum allowed length, and (e) paddled by a super athlete who can track the hull like an arrow and drive it way over hull speed, that -- under such a radical package of speed performance characteristics and specs -- you can then take the liberty of reducing wetted area with some end rise (rocker) without risking energy-wasting boat yaw.
I also wonder whether the bow rocker allows the hull to "climb over" the bow wave more efficiently in a sprint boat.
However, a particularized package of sprinting specs may not be particularly good for other running or paddling usages. And this thread is about touring boats not racing boats.
Premises: Bolt can't win a running race over 200 meters. An ICF sprint canoe can't win the General Clinton or the Molokai (and wouldn't be enjoyable to tour in at all).
However, it would be the fallacy of hasty generalization to conclude from those factual premises that long armed runners or swede form canoes can't win marathons.