Actually, if one defined an XML or SGML DTD, you could inter-weave text and mark up seamlessly without having to create yet another markup language; another reason to standardize is not having to write readers/writers/converters again and again.

Buy @red pepper{2}.

versus

<recipe> Buy <ingredient amount="2">red pepper</ingredient>.</recipe>

For the latter, standard tools like xmlwf or any good Web browsers built-in XML viewer already exist and work right away.

In any case, double maintenance of JSON and human-readable text will eventually lead to inconsistencies.