of course we still need to have faster speed!, for example when you do video editing. the final compile will wast you a lot of time. or when doing 3D render, faster computer will render faster!

for example : before OC video compile need 2hr, after oc it might only need 1hr 30 min.

or 3d render, it might need 15 hr to render a ray trace image before OC, after OC it might only need 10 hr. don't you think 5hr is a big difference?

people work in 3d company usually ran their 3d during weekend, if the computer is not faster enough the Job might not be finish before they come back next week. so Fast computer is sure needed.

your example is not suited for CPU. CPU is not CAR!