LLMs are very good for confident experienced learners, who are good enough at learning, that they can choose their own learning directions efficiently. For these, LLMs are useful because of how flexible they are: you can go in any direction you want with low cost

If you don't already know how to learn, you should probably follow a syllabus or text or something rather than try to make your own syllabuses. The LLM is probably less useful for you in this case

You might say the LLM is just hard to use in this case - you don't know what questions to ask it. I guess you could start by saying "make me a syllabus" but at that point you're kind of losing the core flexibility value of the LLM, might as well use a textbook