You use yaml to write code to some hidden programming language that doesn’t have any kind of formalized syntax.
Want to add a value to a parameter in your function call? Since there is no specification your IDE can’t help you look up parameter or function names.
Want to do a for-loop? Maybe some functions will support looping and other won’t, because looping is just a ` - loop-while: “a = b”` (or maybe it is double equal signs, who knows, because there is no actual IDE support.