You're effectively defining a serialization format using a subset of xml. You can do that with JSON as well, adding "type" properties as required. The problem

You're effectively defining a serialization format using a subset of xml. You can do that with JSON as well, adding "type" properties as required. The problem is that everybody has their own subset of xml for serializing objects, while for json you can load arbitrary json into a straight-forward tree of dicts, lists and literals. If receive arbitrary xml the only way to process it is with xml-specific tools because the object model does not map to any programing language.