@uniq I think it's more of an emergent pattern than guided effort. People just trade freedom for convenience all the time, and one day the providers notice they can capitalize on it.
@architect YAML is the human readible middle ground. It's more expressive than a flat key value pair such as .ini but still unencapsulated unlike json so it fills a wide range of use cases.
I find yaml ok when used on low complexity stuff, but it becomes terrible when used for anything more involved.