You and parent raise fair points, but I think this approach is a good compromise between the structure that you get from markdown and the aesthetics that ConTeXt is able to achieve.

To expand on your point, it's true that this approach does not automatically fit a given amount of content neatly into N pages, but I don't think there exists a system that can; you'll always have to iterate on what exactly to include if you want to have exactly N fully filled pages, regardless of your document processing workflow.

I believe there is a medium between the two. Keep your data structured, then when you're satisfied with the content, paste it into in-design and work on the layout.