What do you mean exactly? Audio conversation only? If so I don't see it very practical for most of the things
Voice interfaces can be silent.
I think that we are now in the realm of diminishing returns regarding these chat assistants.
This is a truly damning comparison. In Star Trek, the massively powerful ship's computer is mainly ignored in favor of touchscreen interfaces and the natural language voice controls on the computer are mainly used for making tea and occasionally asking a question, which the computer often can't answer or answers incorrectly. All real work is done using other interfaces.
The home and widgets screen can be customized to the point you don't recognize it as iOS
> devs customize the UI
Have you used Spotify? It completely ignores Apple UI and does its own thing cross platform. If you mean let devs customize the OS' UI, why would they? UI consistency is one of Apple's core strengths (or so it was before the 26 releases).