But you don't have to use any more of the XML-related standards than you want to. You can ignore schemas, and add-on technologies like XPATH and XSLT and just use XML as a hierarchical tag-value format, just like JSON.
At this level they are both about equal in complexity: JSON has data types that XML doesn't, and XML has attributes and CDATA that JSON doesn't. JSON syntax is more succinct, but XML syntax is more regular.
XML is good for documents that don't have a regular markup (XHTML, DocBook, JATS, MathML, etc.) where you can mix content elements -- e.g. italic annotations.
JSON is good for structured data/records such as serialized data structures found in RPC protocols.
They both have their own pros and cons that make them suited to different use cases. Choose the one that best suites your data model and use cases.
