I´m not sure if I did speak about that.
Now, if we export a book (pdf - ebook …) each book save the information in one place. If the installation is controlled by one administrator (like a school), all the books belong to the same organisation. To export the books and to save each one in a different place, makes imposible to control how many copies of each book we have and to delete those that we do not need anymore.
Why we do not have in the root theme a place (in the administration page) or in the Super admin menu a place where we can see all the exports that exist and to download or to delete all of the versions that we do not need.
it would make much faster the backups as we can have a better control of the exported formats.
Also to decided wich books to export and wich format. Or even if we whant to allow to download or not.
Having also the copies of each book in one common folder under the root site will make much simple the backup process. Since that is the place if a installation of PB whant to make a paid site where the customers will pay for the subscripion or the books, to have also the books will allow to use a system of profesional backups like vaultpress and to pay just in the root site. because all the important information would be there.
thanks