Here are two ways to think about why a StartWithXML workflow can be important and valuable:
1. Until very recently, we lived in a world where the book was the sun and everything else orbited around it. Now the CONTENT, the IP, is the sun, and the book is relegated to one of the satellite bodies (still often the biggest, but it is a lot different to be Jupiter than it is to be the sun!) When what is at the “core” is different, the processes to create it have to change.
2. A StartwithXML workflow effectively makes the content file into a database. Just about any information relevant to the book, or any piece of the book, can be associated to the content in an XML file, just as it can in a database. Up until now, this has been seen primarily as a tool for production: the database holding information about document structure that translates into the presentation in each iteration. But the capability applies just as well to rights data, marketing data, or fragment identification.
Can these things be accomplished in other ways? Almost certainly, yes, but XML has the advantage of being an accepted standard, and although it may (will) require some dialog between entities sharing it, using XML is the fastest way to enable machines to talk to machines about anything related to a book’s content.