One tool reads the draft, the other dresses the book.
Atticus is built around the moment a manuscript becomes a product. Its formatting engine turns your text into print-ready and ebook-ready files with templates that look like they came from a publisher, and that is what most of its fans bought it for.
DraftProse works on the manuscript itself. The binder holds the scenes and chapters, the editor keeps you in the draft, and the Reader analyses what you have written. The two tools can sit on the same desk: draft and understand in DraftProse, then format the finished file in Atticus.