If you’re using Nix and HM to manage a configuration file for a package that isn’t managed by Nix and HM, you don’t get the same guarantees, sure.

But you also don’t get them at all with Chezmoi, right?

Surely having these guarantees for some packages beats having it for none? In practice _most_ packages you’ll want to use are already in Nixpkgs, and kept up to date.

> You need to actively avoid the "value-added" parts (e.g. package options) because latest Homebrew upstream may give you a version that exposes an option that is not yet exposed by the package options, and you can't patch the package with Nix because you're not using a Nix-based package.

You mean build-time options?

You can usually override the version number/URL in your own configuration to get the new version earlier. But new versions land in nixpkgs-unstable with about the same cadence as Homebrew anyway.

Same thing with runtime options. Want `programs.foo.enableNewThing` but it’s not in HM yet? You can just define that option in your own configuration, no need to stop using the value-added module nor wait for HM.