No, you don't trust the output. You shouldn't trust the output of search either. This is just search with summarization.
That's why there are linked sources so that you can verify yourself. The person's contention was that you can't trust citations because they can be hallucinated. That's not how these systems work, the citations are not handled by LLMs at all except as references, the actual source list is entirely a regular search program.
The LLM's summarization and sources are like the Google Results page, they're not information that you should trust by themselves they are simply a link to take you to information that's responsive to your search. The LLM provides a high level summary so you can make a more informed decision about which sources to look at.
Anyone treating LLMs like they're reliable is asking for trouble, just like anyone who believes everything they read on Facebook or cite Wikipedia directly.