Write a few Helm charts and you'll understand why people want to stop using it. `nindent` will become a curse word in your vocabulary. It's a fine tool at the user level, but the DX is an atrocity.
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.