Growing pains for Fedora CoreOS

In this situation you'd be doing all your changes on the test system first, right? It's not that much of a departure as there would often be a difference between what is running in test and what is in prod, test can't guarantee repro of problems found in prod unless you reset it back to the versions used in prod. There is value in finding upgrade related problems in test first, but as you note the initial advice is probably targeted more toward admins with dozens or hundreds of systems where having a small cadre running bleeding edge code is relatively low risk to the overall system health. The quality benefits of going from prod-only to prod & qa to prod, qa & test to prod, qa, test & dev environments are diminishing while the cost increases but its the scalability of work that goes up the most which is mainly of benefit to larger organizations.