When several documents are bundled in one book, then it is not a bad workflow. Why should it be. There is not even one disadvantage. Only if you see several documents as disadvantage. But they are bundled in one book file! You are way more flexible to work with chapters what you could not do with a single document. You have access to every export function from the book panel's flyout menu (except SWF). I don't see how your solution will work, when chapters have to be moved, when changes are done. I think it is way to complicated. To set up one single document as template, and let InDesign do all automatic numbers.
/// And your solution has one huge problem: You have to override items from the master page. In my solution not even one override is needed.
Overrides are always to be avoided because it will mix content with items from the master which is not logical permitted in a workflow and it will it make difficult to export PDF/UA where content and master is strictly divided.