It's one of the things you just can't do without once you become accustomed to it. I can not imagine going back to needing root privileges just to install or try a package, or being unable to roll back to earlier revisions.

I hear Nix even works on macOS too! :-)

How does using nix on other distributions work? Can it access their local packagemanagers and install the distribution-packages, or is it a parallel world that just happens to live on the same machine?

nix doesn't have a package on OpenSUSE so you need to manually instlal, guix does have one though