Is there much to be gained by using physical hardware like this as opposed to a bunch of VMs? I get that plugging in cables and flashing lights is fun and stuff, but let's say you already have a homelab and are over that. Are there lessons about k8s you can only learn on "real" hardware and not VMs?

I thought about this a while back when there was a global shortage of Raspberry Pis. I'd see people with like 8 of them in a toy cluster and thought it was a shame because some people might have a real use for one but couldn't get one.

You can use things like docker-machine or Vagrant to easily spin up a bunch of VMs for things like this. Also you can use Rancher to automatically provision a cluster for you (but I guess you won't learn as much that way).