For the disabled, particularly blind people, it would be great to have interactive voice stuff if that whole ecosystem were really fleshed out. Some of this exists but a world of audio books, online banking, interaction with social media, all with interfaces optimized for voice use/audio listening would be great.
Interacting with a screen by having some software read it to you just seems incredibly clumsy.
Personally, I think the hands-off case for automotive use is dangerous. Talking on the phone or listening to email while driving is sketchy even though you're still gripping the steering wheel. AM/FM radio interfaces were perfected 75 years ago.