It's removing complexity elsewhere, usually much more. Once you have invested in a relatively fixed bit of complexity, your other tasks become much easier to complete.
Once you have invested in understanding the Clifford algebra, your whole classical electrodynamics turns from 30 equations into two.
Once you have invested in writing a Fortran compiler, you can write numerical computations much easier and shorter than in assembly.
Once you have invested in learning Nix, your whole elaborate build infra, plus chef / puppet / saltstack suddenly shrinks to a few declarations.
> Once you have invested in learning Nix, your whole elaborate build infra, plus chef / puppet / saltstack suddenly shrinks to a few declarations.
Your analogy breaks down with Nix, since learning and using it is a hostile experience, unlike (I assume) your other examples.
I have been using NixOS for about 5 years now on several machines, and I still don't know what I'm doing. Troubleshooting errors and implementing features is like climbing a mountain in the dark.
The language syntax is alien. Most functionality is unintuitive. The errors are cryptic. The documentation ranges from poor to nonexistent. It tries to replace every package manager in existence. The community is unwelcoming.
Guix addresses some of these issues, and at least it uses a sane language, but the momentum is, unfortunately, largely with Nix.
Nix pioneered many important concepts that most operating systems and package managers should have. But the implementation and execution of those concepts leaves a lot to be desired.
So, sure, if you and your team have patience to deal with all of its shortcomings, I can see how it can be useful. But personally, I would never propose using it in a professional setting, and would rather use established and more "complex" tooling most engineers are familiar with.
Once you have invested in understanding the Clifford algebra, your whole classical electrodynamics turns from 30 equations into two.
Once you have invested in writing a Fortran compiler, you can write numerical computations much easier and shorter than in assembly.
Once you have invested in learning Nix, your whole elaborate build infra, plus chef / puppet / saltstack suddenly shrinks to a few declarations.
Etc.