even your bog standard java three tier app gets some tangible benefit from being dockerized (repeatability, whole os image versioning) and placed in a node that abstract everything else (load balancing, routing, rolling deployments etc)
at the lowest level, it's just a descriptor for infrastructure, it impacts nothing of your app or business logic unless you want it to.
even single node testing environments are covered one way or another (my fav now is minikube), the only real limit is one having a requirement for self hosting.