Indentation based structure isn't really a good thing in my eyes, where the format of the document encodes semantic meaning. With JSON, you can display it how you want, and because it's bracketed it will still encode the same data.
Also I really don't like the hyphen notation... This is very unreadable to me:
I know which one I prefer :) Silly example perhaps, but once you have X lists nested in Y lists, it does become a lot easier to see why some prefer a bit more visually hierarchically stronger syntaxes
My belief is that anything that requires more than that are hiding the fact that what they truly need is a DSL. Instead they force you to write AST (ansible, github actions, docker compose,…)
Also I really don't like the hyphen notation... This is very unreadable to me: