Comment by pc86

I was just dealing with this is some home-grown configuration nightmare where every line of the file was pulled from some other namespace to the point where you end up with two dozen folders, each with half a dozen partial configuration files in them, and it takes half a hour to figure out where a single value is coming from.

I'm sure it's super flexible but the exactly same thing could have been achieved with 8 YAML files and 60% of the content between them would be identical.