Nix is a wonderful technology. But I would not argue it is practical if you can afford "just fix it when it breaks". A nix setup more/less requires you to pay all the cost up front.
I appreciate putting in the effort now so that I don't have to later for stuff like declarative dev environments. It's really nice to not have to copy-and-paste installation instructions from a README. -- I did like the point: until you've felt what a comfortable design is, you cannot imagine it.