The difference is the collection of extremely powerful parsers, tooling, language support, etc that already exist for this syntax. There's a proper Content-Type header, blazing-fast native parsing in web apps, you could store it directly in MongoDB or the like without an extra serialization/parse step, you could query it with jq. Heck, you could statically-check these expressions using TypeScript.

Lispers are always pointing out how the parenthesis-and-whitespace notation is just incidental; how s-expressions are really something deeper that isn't bound to a specific syntax, and how this is a strength. The OP is a demonstration of that strength.