I thought "too complex, too much of a timesink" and that kept me from trying it for a long time. My experience is different.

If you are at all idiosyncratic about your setup, using Nix is better than whatever pile of bootstrapping bash scripts you've kludged together over the years.

Absolutely. I'm about a year deep on nix / NixOS and still spend way too much time refactoring things to be more DRY or what I think might be more idiomatic or maintainable going forward (as opposed to a more obvious but uglier approach). Definitely makes it easy to waste time prematurely optimizing, if you're prone to that sort of thing.

The difference is that with Nix, you'd always have a working configuration. With traditional deploy tools, scripts stop working at the most inconvenient timing because they're not reproducible.