I'll never use it. It's completely useless to me. But if my grandma actually did anything else than Facebook on her computer I'd show this to her.
Well.. and we're just fine with it. Simple works better somethings and why be in such a hurry sometimes. I look at these young whipersnappers who fly around the computer with windows attacking from all directions. They just seem to make things complicated without actually meeting the goal any faster.
Maybe once speech recognition advances a bit more...
It's very easy to think of instances where this will be helpful.
* Mobile version of Firefox. It might be easier to talk to fill a form on mobile than type on glass screen.
* Accessibility. There is a huge under served demography of people who will welcome this as typing might be hard for them.
You may not be on any of the groups above but that doesn't invalidate the features.