Originally posted by Ace
Touch-typing is for, as Kazan would say, primitive mundanes. 
It's called remembering where keys actually are.
Well DUH. That's why it's called "touch" typing. With physical keys, touch-typists can lay hands on a keyboard in the proper position without having to so much as glance at it. Without that physical feedback, you would continuously have to be glancing down to make sure your hands were in the right spot.
Also, virtual keys on a flat surface would obviously have no physical travel. Imagine how your fingertips would feel after a day of mashing them into an unyielding tabletop. Or conversely, having a detection mechanism so sensitive that you can barely rest your fingers on the keyboard without making accidental keystrokes.
I should point out that the very first home computer I used extensively was an
Atari 400, which had a flat membrane keyboard, and using it was utterly horrible. Even though it had slight ridges molded into the plastic around the keys, it was still a pain in the ass to touch-type on. So I'm speaking from experience here.
