Based on my experience, I assume Siri is not capable of anything more than setting timers or referring me to my phone to see the search results.

And that’s pretty much what they show in the demo, plus asking it for directions on Apple Maps (which it can also do already), and searching for pictures on the Photos app (which I just tried and it can’t do - so it looks like that’s the main feature)

If it's going to be anything like Gemini on Google Pixel, it'll be great at everything except for trivial tasks like setting timers :).