[grumbel]

Nix allows you to install packages without naming or version conflicts. It allows you to make source repositories act as first-class packages. It can be installed on any Linux distribution and MacOS. Changing and customizing packages is trivial. All the building and installing happens outside of the source tree, so you don't clutter up your $HOME. It's reproducible. It's simple. And it's build with the needs of Free Software in mind (unlike snap or flatpak which seem mostly concerned with packaging proprietary software). Also Nix is 20 years old at this point.

Simply put, with Nix I can do:

   nix run github:project/name

to run a program. Not many other package managers are capable of that.

[Tomis02]

That's cool but Brew seems to work just fine for my needs (and most developers on a Mac, apparently). Which is why I think the question still stands; unclear why people should care when the status quo is good enough.