Unless you are shooting a high powered rifle, you cannot shoot an arrow fast enough to betray an alert whitetail. The idea is flatter trajectory, taking out SOME of the yardage guesswork. JMO
But that doesnt tell me why it would be to fast to hunt with.
Hypothetically... lets say your getting close to some bows advertised speed of , lets say 310 fps ibo. Thats 109 yards per second. We are shooting 20 - 30 yards. Thats less than half of a second from release to impact. Now I know that 310 fps ibo is very rarly achieved, if ever. So say 240 fps, thats 80 yards per second. Still gonna get there pretty damn fast. And a deer that doesnt know your there, will be hit before it hears it.
Correct me if I am wrong, but a flatter trajectory is achieved by a faster bow. The faster the bow, the flatter the line.