I'll also argue that the ideas in this post absolutely matter in practice.

For example, Github Actions uses YAML as its Reader / S-expression / CST layer.

And then it has a separate "parser", for say "if" nodes, and then another parser for the string value of those "if" nodes.

https://docs.github.com/en/actions/writing-workflows/workflo...

    if: ${{ ! startsWith(github.ref, 'refs/tags/') }}

    if: github.repository == 'octo-org/octo-repo-prod'

This fact is poorly exposed to users:

You must always use the ${{ }} expression syntax or escape with '', "", or () when the expression starts with !, since ! is reserved notation in YAML format.

So I feel that they could have done a better job with language design by taking some lessons from the past.

Gitlab has the same kind of hacky language on top of YAML as far as I remember