Thanks! I saved the comment for later.
What advantage do you see in Nix compared to Distrobox?I personally enjoy DB because of its simplicity.I just open BoxBuddy, create a new container from the dropdown-list, and then just start using my Debian or Arch container on top of Fedora Atomic for example.
The two main benefits I see in Nix are the reproducibility and the big repo. But in case of the repository size, Debian and Arch (+ AUR) are extremely big aswell.Are there any other big benefits, that I can't get with Distrobox, but with Nix?Just as a small side note, I'm no power user and tend to use my PC more like a casual guy.

Thanks for your great explanation!How up-to-date are the packages, compared to Flatpaks?
IIRC, I used Nix a while ago to install a program, which was supposedly hard to build for Linux and crashed all the time as Flatpak. Sadly, the Nix version was almost a year old and also not great.
But I think I'll take a look into it again. I began using terminal apps a lot more and also became a huge fan of image based distros, and I think Nix packages have similar benefits as immutable distros.