Yeah I mostly agree. I'd even add that even K8 YAML's are not trivial to maintain, especially if you need to have them be produced by a templating engine.

They become trivial once you stop templating them with text templating engine.

They are serialized json objects, the YAML is there just because raw JSON is not user friendly when you need something done quick and dirty or include comments.

Proper templating should never use text templating on manifests.