I haven't read the entire article, but I assume you need someone to admin the cluster?
How does the savings in billing compare to work needed for maintenance?
[0]: https://cloud.google.com/blog/products/containers-kubernetes...
You can learn the basics of Kubernetes and save around 20-25% compare to use the same Docker Containers but with Cloud Run.
There is a minor cost for one Kubernetes cluster to be run on GCP, but it is negligible if you consider to have some heavy jobs.