What's wrong with `kubectl apply -f xxx.yaml`?

We use kustomize because we have four environments that run basically the same stuff (dev with k3s, test, and two cloud regions). If we didn’t use kustomize, we’d be forced to reinvent it to avoid duplicating so much yaml.

I used kustomize to build an ArgoCD install at a previous company, and I was impressed at how powerful it was. Our setup was pretty involved, and kustomize was able to handle all the per-environment differences easily, and the code was easy to work with.