Had a similar experience. Asked a question about a new language feature in java 8 (parallell streams), and one of the language designers (Goetz) answered my question about the intention of how to use it.

An LLM couldn't have done the same. Someone would have to ask the question and someone answer it for indexing by the LLM. If we all just ask questions in closed chats, lots of new questions will go unanswered as those with the knowledge have simply not been asked to write the answers down anywhere.