Don't you need to run everything in bare metal to effectively leverage microVMs? AFAIK, unlike containers, you can't efficiently run microVMs on cloud VM instances.
You need nested virtualization, which many VMs support -- it is architecture dependent. But, yes, to maximize the benefits you'll want to run on baremetal.
From the standpoint of a cloud user, the kind that likes Dokku, the experience is cheaper/faster/more secure if the infra uses uVMs vs containers.
