Mapping from paper is still mapping
Whether you map fields from an EDI file or from a paper/pdf document, you still have to decide on standards, even if internal, and define the mapping processes. Processes which may, and probably will, evolve over time as needs change.
What is the advantage for the vendor to generate a paper invoice from their internal electronic data format , just to have the customer reconvert to their own format for automated processing? Why not just transfer an EDI invoice and eliminate a redundant step or two?
Is this article just an advertisement for a single company who is now in search of a market for their expensively acquired technology?