You don't need wide adoption for internal projects in an organization, but you do want great toolchain support. For example, the fact that NestedText is a Pyth

You don't need wide adoption for internal projects in an organization, but you do want great toolchain support. For example, the fact that NestedText is a Python library means a Python team could use it, but it's a poor fit for an organization whose other teams use Go and JavaScript/TypeScript. We use YAML for much more than configuration, by the way. I feel like YAML hits a nice sweet spot where it's usable for almost everything.