The initial example is broad, but can't this just be extended with additional questions? For example, can you tell me about dinner options that cost less than $20 per person. What are other people saying? How far away is this? It's questionable whether each of these follow up questions is actually that complex. I think you are arguing that things get hard if a user tries to put that together in one single complex query. Do people do that though?
I think the idea with a conversational interface is that it's succinct and on-demand. You receive the most relevant information directly in as simple of an interface as possible (arguably).
I think the idea with a conversational interface is that it's succinct and on-demand. You receive the most relevant information directly in as simple of an interface as possible (arguably).