Well, you don’t need to learn nix as a programming language for a simple installation, you can use it like a slightly different job, which the configuration.nix part was about. You can get the reproducibility aspect from just that, so I wouldn’t say you get no benefits at all without learning the language.

There are more disadvantages (like time required to rebuild because you added a single package), so Arch is the better choice depending on preferences. Arch is a very good traditional distribution in my opinion, can’t go wrong with it