The author mentions this, and I very strongly agree. What JSON significantly misses is the ability to have comments in your configuration files. I'm not going to hold up the Apache config files as an example of amazing config formats, but... here's an example: https://svn.apache.org/repos/infra/websites/cms/webgui/conf/...

That's awesome. It describes options that are available and not enabled, and what they do. Right. In. The. File. Comparing that to, say, webpack config... there's a pile of research needed to figure out what options are even available, let alone what they do.