What immutability do you mean? Same as snapshots? Or same as templates for deployment?
oci images are by nature not modifieable, if you restart a docker or podman container it will relaunch the service from scratch, loosing every temporary data except the one on attached volumes. This is a good thing since it allows a clean restart in case of an error. It also helps to ensure that nobody tampered with your image:
https://docs.docker.com/dhi/core-concepts/immutability/
https://medium.com/sroze/why-i-think-we-should-all-use-immutable-docker-images-9f4fdcb5212f
These benefits are lost if convert them to normal, modifieable lxc containers. Normally you would want to run oci containers to profit from their immutable nature. With lxc you also will have an environment which behaves slightly different then the one the software on the oci image was developed for . Aka: Support might be an issue which makes this imho a big no for professional environments.
It's also not possible to use something like docker-compose or podman quadlet files (which makes spinning up new services rather easy) with the current state of the feature.
Maybe re-using existing OCI infrastructure in Proxmox environment too, I think.
I doubt this. Usually you run oci-containers from a (virtual or physical) Linux server with docker or podman.
Imho there is no usecase in a professional run infrastructure, that's the reason I'm asking
And I'm not sure whether it's a good idea to appease homelabers who wants to "save resources" (because vms are oh-so-resource-hungry (they are really not)), they usually don't buy subscriptions. So I don't see much ROI for the new feature