I think another way of looking at this is what can you do to make critical systems more robust and resilient. The capability to monitor, deploy, and rollback n

I think another way of looking at this is what can you do to make critical systems more robust and resilient. The capability to monitor, deploy, and rollback new features/fixes on short notice would seem to be a part of that, even if actually used infrequently. I would think that you would need to be able to respond to a change in the environment the system is operating in as much ensure that a new release doesn't contain bugs that would manifest in your current understanding of the operating environment. I am suggesting that much if not all of the infrastructure needed to reliably patch/rollback critical systems can also be used for continuous deployment at the option of the development team and/or the customer. So in the event that a P1 hit a continuously operating network application (e.g. power grid) the ability to deploy and rollback new features rapidly in response might be a valuable option to have. It's an approach that increases resilience. This does not mean you have to do this all of the time.