The description, prompt settings and website look like an extremely early prototype - nothing I would spend 19$ on.
If you want people to have an idea about output quality, you should provide reading samples. I personally hate the idea of seeing AI generated books in stores and I suspect publishers will reject them.
But there is a market of people ordering personalized cups, tshirts, puzzles and mousepads, so you could try to tailor the marketing to this customer group.