I think this is clearly the way forward for Apple. The rest is just UX and refinement.

I recently set up a Shortcut on my Apple Watch that lets me bypass Siri and talk directly to ChatGPT. I used a custom pre-prompt in the Shortcut to tailor the length and detail for watch use. I have 2 versions I can launch from my watch face, one that responds with voice and the other that response with text. I find myself using them all the time, it’s so convenient to be able to ask any little thing that’s on my mind. A version of LLM Siri with full access to the phone and application APIs would be like a superpower.