I think the most useful part of the courses, is when we learn how to organize your ideas before actually start writing the essay. This organization skill can be used not only in writing but also in another field. Organization and drafting skill can help you develop your own ideas, and plan it in a way that the whole writing experience would become smoother.
I have also been using the level of editing. Previously, before I took this course, I would only check the grammatical error and the sentence structure. I would edit my essay in an unorganized way. After I took this class, I start to follow the level of editing to write my essay, the flow of essay writing become easier.