It confuses a lot of people, because Nix breaks down the boundaries of what we traditionally see as separate tools. If you have a sufficiently powerful language

It confuses a lot of people, because Nix breaks down the boundaries of what we traditionally see as separate tools. If you have a sufficiently powerful language to describe how to build things, you can build packages, container images, operating systems, etc. with it. Probably the closest equivalent outside Nix/Guix is Bazel or Buck (not the same, but they have many overlapping goals).