The real value is the Install / Life Cycle orchestration - vanilla K8S has really marked that firmly as "not their problem" - which is the correct thing for them to do.
Hopefully, but Cluster API relies on something like Rancher (or AKS/EkS/GKE) to do the deployment underneath it - it still kind of outsources the life cycle.
Some of that is easily done with Helm and kubeadm, but not all of it, and definitely doesn't scale as you grow the number and size of the clusters running.
