It's devilishly difficult to get citations in there, you're not going to do it with langchain, but its possible (c.f. Bing).
Python x langchain x LLMs makes it very easy to create demos so there's been an initial influx of meh stuff, I'm very excited for 6 months from now.
I've used for rather obscure queries and liked the summary the AI wrote as well as the links to dive deeper. I imagine that's what AI search will look like across all providers before long.
I threw in a question Wikipedia does kinda answer but leaves a lot of details off, and it enumerated a set of possible answers, with my favored option linking into a forum where it looks like less than a dozen people post, but with people that tried all variations of it and know all of the details.
DDG and Google would never show me that site (yeah, I've tried).