I'm starting to feel that the whether or not you need Kubernetes is closer to old conversations related to whether or not you need a dedicated DBA. Can your organization survive and recover with hourly/nightly backup restores to recover from an incident? Is your replication so complex that you really need a guy to ensure that's never getting into a bad state? Worse case scenario can most people working on the project restore the database to a valid state if something does go wrong? I feel like these questions have similar representatives in whether or not Kubernetes is right for an organization.

Kubernetes also makes more sense if you look at it as a common way for an organization to run applications among disparate teams with a shared operations infrastructure. It provides a standardized model for things to work the same enough to work the same. If you are only delivering one kind/whole organization thing and it all looks and quacks like a duck maybe you should just deliver a duck instead of putting a duck hat on Kubernetes and asking it to quack.

I don't think there is anything wrong with designing an application that would transition easily into Kubernetes but I feel like many of the proposals/PoC I have seen in the last few years are either fresh systems that get consumed by Kubernetes complexity or are poor replacements to systems that already exist and only seem to serve as resume padders for the team architecting the replacement which gets a viking funeral as soon as they leave. Often the latter case is because the underlying architecture and goal of the system is pre-Kubernetes and doesn't fit the model well of having mostly stateless/replaceable pieces.