The problem with this approach is precisely that these apps/widgets have hard-coded input and output schema. They can work quite well when the user asks something within the widget's capabilities, but the brittleness of this approach starts showing quickly in real-world use. What if you want to use more advanced filters with Zillow? Or perhaps cross-reference with StreetEasy? If those features aren't supported by the widget's hard-coded schema, you're out of luck as a user.
What I think it much more exciting is the ability to completely create generative UI answers on the fly. We'll have more to say on this soon from Phind (I'm the founder).