Yes. I think the main reason is that json maps so nicely to native types like dict, list, string and double. xml is usually deserialized to a dom object and accessing the right things is a bit more annoying and complicated.

Another thing with xml is that if you give it a finger it tries to take the whole arm and guilt you into using more and more xml technologies like xsd's and dtd's and namespacing and xslt's and before you know it you are neck deep in xml arcana.

Json is also more terse but that's less important.