[kolla-ansible][Yoga] What are the benefits to run libvirt daemon on host rather on a container?

Hi, What are the benefits to run libvirt daemon directly on the host rather than on a container? In Yoga's release note, it is said : "Currently this is only supported for fresh deployments without an existing nova_libvirt container" But Also it it is said : "Adds a kolla-ansible nova-libvirt-cleanup command, which may be used to clean up the nova_libvirt container. This may be useful if switching to a host libvirt daemon". Is switching supported? I am in ther verge of upgrading from Xena to Yoga and I ma wondering about this. - What is the gain to use libvirt daemon? - Could the switch be done after the upgrade to Yoga? Regards.