XSLT and XPath is about the only reason I can see to use this. But, you know, how hard is:

   x.person.addresses[0].city?

I guess XPath is easier when you probably have to do something like this:

   JSONObject json = (JSONObject) JSONSerializer.toJSON( jsonTxt )
   String city = json.getJSONObject("person").getJSONArray("addresses").getJSONObject(0).getJSONObject("city");

Or however you'd do it in Java.