[aszen]

The only reason you would want packages from different distro's is if they have a different version.

With nix you can install packages with different versions, you can also install old packages by going back in nixpkgs history and building the package.

Nix being source based means you can install any software package as long as you have access to it's source.

Ofcourse some of this is possible with other systems too but the nix ecosystem makes it far easier to build packages in different languages.

In short nix can treat the disease (missing different versions of packages in distros) instead of treating the symptoms (installing packages from different distros)