XML the data format is pretty great in its basic form. Not space-efficient, but unless you're dealing with bulk data, the inefficiencies don't matter unless you're googlescale or can't spare a millisecond. The format itself doesn't absolve you from the design work of your model; your ssn example is typical of the "CEO said we have to use XML now" rush-jobs at the peak of the SOA hypecycle.
XML data validation through XSD is a dream. The insistence of the JSON-people to sabotage any kind of data validation is absurd to me.
XML Webservices are easy and consuming them from a WSDL is easy.
SOA on an enterprise level was a stupid idea creating a giant expensive communication middleware with the ESB without delivering on the promises.
Every other thing in the XML space is brainfuck-level overcomplicated bullshit dreamt up by bored enterprise architects. WS-* is a cacophony of overcomplicated solutions to problems that only exist because enterprise architects dreamt of having a single data model that's inter-operable between companies.