You raise an interesting point. I agree that discussing a subject with a knowledgeable mentor, AI or otherwise, is a great way to learn. But I think back-and-forth discussions are limited as a means of testing your mastery of a subject. Especially with complex and nuanced subjects, being able to organize them in your mind is an essential part of mastery. You will not know if you have mastered them unless you can generate a clear and coherent description of them entirely on your own. With a mentor prompting you, step by step, you are relying in part on the mentor’s understanding of the subject to guide your thinking.

It is like the difference between multiple-choice and essay exams. In the former, the questions you are asked reveal much about the structure of the subject to be explored and of the relative importance of its facets and the many nuances within. In the latter, you are on your own: you must conceive of a coherent map, render its form onto a blank sheet, and populate it with what is important, with everything being sensibly connected.