DevOps, CI/CD and Automation

I can't find any true tangible benefits to using XML
to transfer data from legacy systems, in comparison to say, using an external file and loading into existing
schema objects, which we do use.

We have 4-6 internal systems, and many many external systems, that currently use text or DB links to transfer data around, and of course the manager hears the catch-phrase-of-the-day XML, all time time and wants us to use it. We do a lot of complicated reading of the files, i.e. headers and multiple layers of detail (header & detail lines can have infinite detail lines)

Can somebody offer up why use XML? (white pages, something I can get proof with) or why not to use it.

To me, completly different layer of technology, everybody has a "standard", nobody has the same standard.
More storage in the database (being a DBA I don't like this), and seems to need its own full time employee to manage it (the IT director won't like that).