The thing I am always curious about with voice controlled devices is how do you use them in public? On the bus? Subway? How do you discretely check a message while in a lecture hall?

Voice control makes for a fun scifi gimmick but it is incredibly impractical in real life without an alternative interface, in my experience.

This. Speak to type I can understand, to a degree, but for proper voice control to be quick and effective and anything more than a gimmick, it would need to rely on some shorthand - kind of how full-on screen reader action for those visually impaired is very intense - just the other way round.

You would still have a screen. The device itself could just be smaller.