I don't get it, this looks like what I'd expect it to show me if I asked it to find a certain message. I assume tapping on that message would bring me straight to that point in the conversation.

I believe that is showing the results of a search, as in something like "What Plant was Aga telling me about the other day?". The website doesn't make that clear but they asked questions like that in the keynote (not that specific one).