Not entirely sure what this is doing at first glance beyond providing a plain textfield for text entry, and some controls to save it as a file.<p>Compared to something like this:
<a href="http://jsoneditoronline.org/" rel="nofollow">http://jsoneditoronline.org/</a><p>Which has auto-parsing, auto-formatting, and relatively intuitive controls for manipulating the object structure inline.