To me, the #1 reason to use YAML rather than anything else is if you need to embed complex multi-line strings in your document. This is a practical necessity in

To me, the #1 reason to use YAML rather than anything else is if you need to embed complex multi-line strings in your document. This is a practical necessity in CI systems: you always end up with at least a little bit of shell scripting to glue things together, and embedding shell scripts into anything other than YAML is an absolute nightmare. Yes, there are too many options for expressing multi-line strings (In the vast majority of cases, I really don't care whether it has a trailing newline or not). Yes, there are weird rules that don't make sense, like how in "folding" mode a newline followed by two spaces more than the current indentation level doesn't get folded. But it's still the best option for CI, which is why Github actually ditched HCL in favor of YAML after a while: https://news.ycombinator.com/item?id=20647691 https://news.ycombinator.com/item?id=20647691