Kind of impressed by Apple's commitment to security with their AI nonsense (especially in comparison to Microsoft). That said:
First, I'm not sure I trust anything powered by OpenAI.
Second and perhaps more importantly: I can't see where the profit is in this system; you're talking about an investment in a bunch of specialized, rapidly outdated hardware that is costly to run to add a few bells and whistles to their phone experience.
I expect this to end up a pretty expensive premium service.