NixOS aside, Nix manages state _outside_ of / independent with respect to your operating system, which is why it's so damn useful.
With Nix, I can build OCI images the exact same way every time; with Docker, I have to hope that the `apt update` thrown in at the top doesn't accidentally put me on a new major version of some dependency that breaks the rest of the script. I tend to deal with Dockerfiles written five or more years ago, so I will admit to bias here.
I'll also admit that I don't really enjoy NixOS. It's neat enough on my headless devices but not something I'd want to try to daily drive; I'm more a fan of the Universal Blue / Project Bluefin approach.
With Nix, I can build OCI images the exact same way every time; with Docker, I have to hope that the `apt update` thrown in at the top doesn't accidentally put me on a new major version of some dependency that breaks the rest of the script. I tend to deal with Dockerfiles written five or more years ago, so I will admit to bias here.
I'll also admit that I don't really enjoy NixOS. It's neat enough on my headless devices but not something I'd want to try to daily drive; I'm more a fan of the Universal Blue / Project Bluefin approach.