Comment by galvin

Somewhat tangential, but the EU has a directive mandating electronic invoicing for public procurement.

One of the standards that has come out of that is EN 16931, also known as ZUGFeRD and Factur-X, which basically involves embedding an XML file with the invoice details inside a PDF/A. It allows the PDF to be used like a regular PDF but it also allows the government procurement platforms to reliably parse the contents without any kind of intelligence.

It seems like a nice solution that would solve a lot of issues with ingesting PDFs for accounting if everyone somehow managed to agree a standard. Maybe if EN 16931 becomes more broadly available it might start getting used in the private sector too.