top end Speed is harder to improve then acceleration, because it Needs good running form and more natural Talent. accelerating on the other Hand can be improved by getting stronger, even with poor running form.
I was a shot putter when I was a kid and for about 20 meters I was almost as fast as some quite good Sprinters in our Club because I had strong legs. over a full 100 I was never fast at all because my top Speed and Speed endurance was poor.
I can thus see top Teams wanting to know the top Speed of a Player.