I think a better way to understand is talk and discuss it rather than just write about it. AI can be useful for this, like instead of it lifting for you, it is holding the punching bag instead in your metaphor.

Yes, writing clearly makes you understand your thoughts etc. But it is one of the methods and we shouldn't extraploate how much a person understands things based on whether they write or not.

Arguments and discussions are still superior form of learning to me than just purely writing and thinking.

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.

One is getting guidance and another is using that guidance. They are not substitutes.

Zen teacher talks with students, but then the students work on their own. They cannot get that knowledge in a dialogue. In Zen the situation is clearest, but it is same everywhere, e. g. in math.

The problem with talking and arguing is that many people push/flood the discussion with low-quality arguments. This puts it back on the person trying have a good discussion to keep correcting or defending.

A public example of this is Trump who just overwhelms any discussion with bullshit. It's impossible to have a conversation where anyone learns something.

Writing lets all participants operate at their own pace, and the type of person who tries to overwhelm a discussion with bullshit often doesn't write very much.