[debarshri]

A good example from my perspective is when you are delivering an application as 3rd party vendor and you wish to automate lot of operational stuff like backup, scaling based on events, automating stuff based on cluster events. It starts becoming very valuable. I am sure there are many more use cases for.

[jrockway]

I would not write an operator to do any of these things. To me an "operator" strongly implies the existence of a CRD and the need to manage it. So for autoscaling, HPA/VPA are built into k8s. Backups should be an application-level feature; when the "take a backup" RPC or time arrives, take a backup and dump it in configured object storage. Automating stuff based on cluster events also doesn't require an operator; call client.V1().Whatever().Watch and do what you need to do.

The only moderately justifiable operator I've ever seen is cert-manager. Even then, one wonders what it would be like if it just updated a Secret every 3 months based on a hard-coded config passed to it, and skipped the CRDs.