Ah but then you are talking about servers? That would be a different story! The machine that I use for development (laptop) should always work (I would trust nixos with this) and if I want to spin up a container (docker run) or install an application (apt install)or change my vpn client configuration it is currently effortless and I'm not sure nixos can do that.

Actually using nixos for some of my private servers would be a nice use case...