I'm not too sure what niche MicroOS is supposed to fill that JeOS and the full-weight Leap don't already cover.
MicroOS just seems to be answer to RedHat's Silverblue, but with no clear use case in the SUSE/openSUSE product lineup. It makes some sense as a tech demo for an immutable OS, but not much sense as an operational product.
MicroOS it's a cloud OS linux, more like: CoreOS, RancherOS, AtomicOS. I think it's a default choose for Kubernetes environments.
I've been using JeOS for k8s hosts of Rancher environments since RancherOS was deprecated and I'm glad that they finally released a cloud OS like MicroOS. In case of k8s upgrades, rollbacks and upgrades need to me minimised as much as possible. This OS allow to have all of that in a breeze since it's all based on static images.
I am curious what exactly this is envisioned for. Running micro services do not require such things and the system requirements are so heavy, it would need more hardware to run that just running them all in a normal distro.
I never jumped on the container bandwagon since it seems like it adds overhead for very little gain that can't be done with much lighter solution.