Well, there are plenty of people with severe carpal tunnel syndrome who are always looking for new ways to interact with their computers. There are even some mice that can be used with your feet. From what I can see, that keyboard would be pretty useful for physically impaired people who might not have the manual dexterity to type a bunch of keys quickly. Although it does cost 400 dollars.
Of course, but that doesnt make it any less stupid looking. My boss used to use this:
and it was a real hoot to watch him type. The little mirrors on the sides are obviously so you can see the keys but they even took the extra step of printing the letters backwards on the keyboard so they would show up correctly in the mirrors.