Yeah, it does make sense that you can compare them in that sense, but as far as actual system setup goes, I don't think they're comparable. Don't get me wrong, I love NixOS. When I was learning nixlang and setting up everything to be modular and reproducible, I was having a blast.

However, I also had a blast learning Arch and figuring out how my system works the way it does. I'll be honest, though, NixOS helped me learn how Home was separate from Root. That alone really helped me learn how the general Linux system file hierarchy worked.

But there are also things I would have never learned about Linux if I never messed with Arch, such as essential system symlinks, how they work, and how to use chroot in the live environment to fix broken ones (thanks to a botched Arch update, lol).

If you like it, learn it-use it. All this comparing and inter-distro warring seems pointless. There's not a distro I've used that I haven't had things I really liked and really hated.