docker compose is beautiful because it uses a simple elegant compose yml file - this is now an open standard. https://www.compose-spec.io/

the standard does not make it mandatory that underlying system should be docker compose (the reference server). it can be anything.

IMHO - kappal is the first project that takes your compose yml file and transparently/drop-in runs it on kubernetes. there is nothing extra you need. It is useful for people who want to maintain their stack as close to production as possible (kubernetes).

If that's not a big goal for you, then this is not very useful for you. But I'd argue ...why do you care if the compose yml is the only think you are using. you get all of kubernetes.