I think there's a use for it in the world of phones..
When typing using a keyboard, most people with a bit of experience can find their way around with their eyes closed with reasonable levels of accuracy. Not so with a flat touchscreen. Not necessarily a problem you may think, but the resultant effect is that with a touchscreen you're constantly looking at what you're doing, and your brain is constantly having to process the visual feedback to guide your digits. The effort of doing so can be pretty demanding for some people, and it seems to be significantly higher than processing haptic feedback.. I see it with a friend of mine who had Parkinsons. She can type pretty effectively using a keyboard. Not super-speed, but more than well enough to get by. But on her iPhone it can be a real struggle, as she has to process this feedback without any senses other than sight being involved. And there's little delineation between keys etc, so mis-typing becomes more common as it's harder to keep one's digits in the same place.
Similarly for people with reduced vision, touchscreens can be a total shitemare.
Sure - I hear the "just buy a qwerty phone" cries already. And yeah, I'm pretty sure that's the world we want.. one where people with diminished abilities have reduced choice in areas where we could engineer solutions to provide them with the same choices as others. Shit, why do we even bother with accessible websites anyway? Why don't those pesky crips go read a book or phone a "norm" to look it up for them?