Seems pointless. But it depends on how you spin it. Listing it, well, I don't see the point. But if you talk about how much you learned, how passionate you are about the courses, etc, then it could be worthwhile.
Well, I mention one of the courses that I take in a personal statement. But I just feel that listing them in the additional comments section, as well as expanding on the experience in my personal statement will give it some weight. If I just talk about that first single course that I took in my personal statement. It might look like I went through it, lost steam, and quit on it. I feel like putting those in the additional comments section might really show how I continued with it and persevered.
those are not real classes. it's fine to talk about how you study your subject beyond assigned hw in your personal statement, but it would look really silly if you listed them in the additional comments.