The plugin is so that you can have your own self-hosted solution, which is free to use (minus having to pay for a Prince XML license). If you don’t want to have your own setup, you can use pressbooks.com, but have to pay in order to export your book without any pressbook.com advertising & watermarks. This plugin & self-hosted version contains no watermarks (it does include a notice on the copyright page that you can manually disable if you choose to do so).
