AB, I counter thus:
Velocity's importance could be based not only on going fast enough (to yield effective energy, and desired range and flatness of trajectory), but also on not going too fast.
Most firearms have a sweet spot in velocity for accuracy.
Most projectiles have a velocity range below which, they will not expand, and above which, they fragment - potentially preventing penetration. (Alliteration free of charge.)
So one could argue velocity is more important with regard to finding the ideal velocity for the particular firearm and bullet combo.
That would be a completely separate argument than velocity, solely with regard to energy level.