Just running KDE litters a bunch of dotfiles into your user folder, even for settings you didn't adjust. This is true for many applications.
If you had an empty home folder and passively tried a handful of desktops, you'd no longer have an empty home folder. Hopefully your environment is resilient to clutter being leaked into your home folder, but if your filesystem isn't truly immutable, rolling back to a particular Nix config might not get you the exact state your system was in when you first built that.
There's a project that wipes all local changes when you restart your machine, with the goal of making Nix systems more reproducible. I think it's called Impermanence.
If the point of Nix is to keep a filesystem immutable as long as every app sticks to certain rules, is it actually the right till for the job?
Sorry… I actually don’t know much about Nix given I’ve been using VMs and now containers for over a decade, so just trying to understand the problem that nix actually solves
At the moment I’m using Ansible for the host and Docker for guests, but I see NixOS as combining these two lasers so everything just runs on the host? Is that fair to say how NixOS works? If so and I have it wrong, maybe I should check it out and I’ve been sleeping on Nix all this time
Edit: ok I HAVE been sleeping on NixOS! I couldn’t understand how isolation worked with /etc files, but it turns out /etc is not modified but you do it all through modifying the nix config and rebuild the system which generates /etc! Ok, super interesting
My recommendation would be to test it out and look at how it does things. Maybe checkout the live installer with a gui to get a feel for a desktop system.
It can still write to folders, so it's not completely silo'd off like a full-on Docker container, but I still really like it.