Stack Overflow is a community with an answer-rating system and there is often some level of review from other people commenting on the answer's advantages and shortcomings. You often have multiple answers to choose from too. Those features build trust in an answer or prompt you to look elsewhere.
The UI for an LLM answer would have difficulty replicating the same thing since every answer is (probably) a new one and you have no input from other people about this answer too.
Edit: After writing my reply, I saw that roughly four other people (so far) made the exact same point and posted it a couple of minutes before. I think your question is a good one (made me think a little) and apologies it feels like you're being piled on.
I've never been that fond of SO, but I find chatgpt very useful. SO tends to be simpler one time questions. My interactions with gpt are conversations working towards a solution.
LLMs totally have a beginner problem. It's much like the problem where a beginner knows they need to look something up but can't figure out the right keywords to search for.
Also chatgpt has never called me an idiot for asking a stupid question, having not read the question properly, and making the assumption it was the same as an existing question after skimming it. I wouldn't ask SO a question these days, the response is more likely to be toxic than helpful.
Because on Stack Overflow you also see feedback from hopefully a cross section of the developer community, several methods of solving the problem, voting feedback on those solutions, and can sus out a proper solution vs. just having one answer fed back to you.
Because people on stack overflow don't lie to the person who wrote the question very often. A correct answer to a problem that isn't the same as your problem is a better resource for learning than an incorrect answer to your exact problem.
The UI for an LLM answer would have difficulty replicating the same thing since every answer is (probably) a new one and you have no input from other people about this answer too.
Edit: After writing my reply, I saw that roughly four other people (so far) made the exact same point and posted it a couple of minutes before. I think your question is a good one (made me think a little) and apologies it feels like you're being piled on.