Most people in this thread, it seems, just want a simple way to manage Kubernetes manifests, something that keeps track of different settings for different environments and what's in common for each environment in order to generate the final manifests for an environment. If so, Helm is over-engineered for your use-case. Stick with Kustomize or jsonnet.

Helm's contribution (as horrible as text templating on YAML is) is, yes, to be a package manager. Part of a Helm chart includes jobs ("hooks") that can be run at different stages (pre-install, pre-upgrade, etc.) as well as a job to run when someone runs "helm test", and a way to rollback changes ("helm rollback"), which is more powerful than just rolling back a Deployment, because it will rollback changes to CRDs, give you hooks/jobs that can run pre- and post-rollback, etc.

Helm charts are meant to be written by someone with the relevant skills sitting next to the developers, so that it can be handed off to another team to deploy into production. If that's not your organization or process, or if your developers are giving your ops teams Docker images instead of Helm charts, you're probably over-engineering by adopting it.