They are using the Terraform providers to provision their various ROSA clusters. For their storage solution (PortWorx) to function properly they must label their compute machinepools with:

"portworx.io/node-type" = "storageless"

Currently, the provider and the API do not allow setting default labels on compute machine pools when creating HCP clusters. This means that when/if new compute nodes are added, they must be manually labeled. This makes autoscaling of the cluster unworkable since newly added nodes would not have the labels and would cause problems with their storage system.