Distro agnostic packages like flatpaks and appimages have become extremely popular over the past few years, yet they seem to get a lot of dirt thrown on them because they are super bloated (since they bring all their dependencies with them).
NixPkgs are also distro agnostic, but they are about as light as regular system packages (.deb/.rpm/.PKG) all the while having an impressive 80 000 packages in their repos.
I don’t get why more people aren’t using them, sure they do need some tweaking but so do flatpaks, my main theory is that there are no graphical installer for them and the CLI installer is lacking (no progress bar, no ETA, strange syntax) I’m also scared that there is a downside to them I dont know about.
Note that Nix is not a full-blown programming language, it’s an expression language. The end result of an expression is always data and side-effects are not possible; you can’t do network requests or write to arbitrary files. There is no such thing as a variable in Nix either, only constants. You can think of it like JSON with (pure) functions and an additional data type (~package).
From a user perspective, it’s really not very different from any of the other 100s of weird configuration syntaxes you’ve surely come across in your Linux journey.
My nixos-config is a bit more complex because I like to reap the benefits that abstraction but here’s a simpler section that is representative of how a typical NixOS desktop config would look like:
https://github.com/Atemu/nixos-config/blob/ee2d85dc3665ae3cad463a3eb132f806651fe436/modules/desktop/module.nix#L16-L77
(Though note that even this is slightly more complex than what you’d do when starting out; ignore the LADSPA_PATH and tablet conditional for now.)