Unfortunately, it suffers from the huge problem of not having any comments, which was what the original poster was pointing out. Configuration is code that happens to be interpreted at runtime. Having to dig through uncommented code at two in the morning sucks, especially when you're trying to figure out why your automated code and/or config generator just failed. Yes, having to write a config file by hand sucks, however, there are still enough cases out there where you end up having to do just that, and JSON makes the problem of keeping them lucid all the more difficult.

What I hate is that good tools for this like UCL go ignored or forgotten while JSON formats grow like weeds, and even excellent people like Hashicorp wind up contributing to this serious problem.

Ooh, they still do, especially things by Elastic.