Hardware specifications are important on a smartphone for the same reason they are on a PC. More computing power means you can run more and more complicated applications and games than something not as robust. It also means you could load and run mainstream applications faster than on a device with lesser specifications. Less time waiting is always a good thing. I don't think it being nearly twice as powerful can be considered a marginal difference. The Droid X is faster than the Incredible by a larger amount than the Incredible is faster than the Droid, which is huge.