> But… because it’s Nix I never have to do that again.

This is the killer feature for me. My use-case for Nix is vastly different from yours, as I use it for centralized declarative configuration through NixOS, but I have an immense sense of satisfaction knowing that hell can freeze over but I'm still only a single command away from my exact setup running on (almost) any machine on the planet.

This might not matter much for most people, but making my machine work for me is something that took me years, and I can sleep well knowing that it's finally safe under Nix vs. multiple different configuration files for multiple different programs scattered across my filesystem.