Don't focus on nix too much, sandboxes are the most important point :) Nix is not the only solution, there is also GNU guix for example. Actually I agree that

Don't focus on nix too much, sandboxes are the most important point :) Nix is not the only solution, there is also GNU guix for example. Actually I agree that the nix language is just increasing the complexity, one could have used a already existing language.