What AI can and cannot contribute to a book
AI is exceptional at the mechanical majority of book production: expanding structure into prose, maintaining consistent formatting, drafting at a pace no human matches, and never getting tired of revision requests. It cannot know your reader, verify its own claims, or supply the lived specificity that makes advice credible. The productive division of labor is exactly that split: machine drafts structure and prose; author supplies constraints, truth and voice.
Authors who treat the draft as raw material ship better books faster. Authors who treat it as a finished product ship fluent, forgettable ones.