Well current voice recognition tech makes it a crappy user interface, but it could be improved. It does make a really handy feedback device, though. Much like haptic feedback, humans can detect a wide range of audio cues and use that as feedback in an interface. You probably already recognize the bip on your phone is a Facebook message while the bong is your e-mail alert, and the ding your text message.

Back in the day when I made my own CarPC, I naturally made my own interface for it too, for, you know... reasons. The input was a mini numpad, but the output was audio - primarily text to speech. I could drive around and use the interface (mostly) safely, but be exactly sure of my input choices using the one-handed, nailed-down keypad. Worked like a charm.

If in the future we nail down the voice input to be more accurate, fast and flexible, we can avoid the author's concerns and get something as useful as touch screens but based on our ears and mouths.