I saw a youTube video in which the use of this software was discussed by Jordan and his daughter and son. Jordan’s son explained that he had software writing credentials and that he had put a lot of effort into making the interface self-explanatory. The design was specifically for writing essays, but they noted that proper usage to create an essay is to write way more prose than you plan to publish, then cut it down to size - in the process, necessarily “discarding” text that you wrote and have fallen in love with. Instead of literally deleting such text, the program saves it for future use in other essays.
Bottom line here is that they asserted that their authoring pgm would be serviceable for writing a book by composing it one chapter (“essay”) at a time.
FWIW.