Coming from docker before nix, I think nix is a better version of docker for some use-cases. If the ecosystem is supported then I much prefer nix for speed (both runtime and development speed)
However, I find debugging docker infinitely easier than debugging nix. I played around with the idea of adding nix for work projects and getting buy-in from other colleagues. But after working with it for weeks and still running into issues, there's no way I could in good conscience recommend the tool.
Yep, definitely have to be careful about exposing nix to others. I did it on a 2 man team to great effect, but would really have to vet teammates before doing it on a broader scale. I do, however, generally write all of my scripts with nix-shell shebangs to give a layer of consistency/guarantee, and that has had a couple people ask me about it.