The use cases for YAML that don't involve any sort of scripting vastly outnumber the use cases for YAML that involve embedding scripts into a document; so it's a little unfair and inaccurate to say that "in YAML it's kind of expected".

It is more fair to say that if your document needs to contain scripting, YAML is a better choice than JSON; for the singular reason that YAML allows for unquoted multiline strings, which means you can easily copy/paste scripts in and out of a YAML document without needing to worry about escaping and unescaping quotes and newline characters when editing the document.