I really don't care what a format is called so long as it fulfills the basic requirements: 1) can be written and parsed with the std libs of the language in question, and 2) supports comments if it is to be used by both humans and machines, such as in config files.
YAML is a far superior format to XML for config files, and is basically JSON in a readable format.
There's literally zero reasons to choose to use XML where you could use JSON/YAML instead.