You could also say any automobile with more than 40 or so HP is "overpowered", since that's about all that's needed to get a typical sedan to do 65mph. Why does anybody need a car that could exceed the posted speed limit?
I don't pussy-foot around, my Max hauls the mail every time it goes out. More than once I've "caught" myself on the way home, realizing I haven't opened up the tap yet, and promptly do so at the first opportunity.
The difference between a 400cc twin and a 1200cc V4 isn't just flat out performance, it's ease of riding. With my old GS450, you had to wring it's neck constantly. The twist probably spent half it's life against the stop to keep up with highway traffic. Passing above 55 was dangerously slow or totally impossible. Downshifting (twice) for even modest grades. On the other hand, the Vmax just effortlessly goes everywhere. Never have to downshift for any highway grade, ever(even with Venture drive). Barely have to touch the gas starting off, where the 400 required a considerable amount of revving to get off the line.
A 400 is a mouse fart sent into motion by an ant sneeze, where the Vmax is the hand of God pushing you down the road.