I read the article and the linked blog and I still can't tell what this has over plain Kubernetes deployed on AWS -- what am I missing?

> Storage for applications deployed on Supergiant is allocated on high-availability arrays, however, it does not use Kubernetes' persistent volumes. Currently available on AWS, Supergiant uses Amazon's Elastic Block Store (EBS) so that volumes can move freely around the cluster.

Kubernetes has EBS support, right? What does Supergiant do better here?