I think your point could have been made even better if instead of quotes/numbers/strings you would have illustrated the in-band typing using square brackets and

I think your point could have been made even better if instead of quotes/numbers/strings you would have illustrated the in-band typing using square brackets and arity. Two bytes for "there can be more", so much better than the plural/singular convention often seen in XML (rarely without some creative breaches closely nearby). In hindsight, the biggest advantage of XML over JSON was that it was painful enough to make schemas popular, a quality JSON is lacking. Unlike schema languages, which do exist. To me, XML tooling lost quite a bit of its appeal when I realized that all the typing available via the various schema languages is completely lost to the world of xsl/xpath/xquery. I understand the reasons for that, but that does not provide much consolation.