In my experience those "others" that "just wrote docker files" are exatly the ones that don't know how to build the system in a reproducible manner if their ci environment gets reset for some reason as they find out that stuff that was "supposed to be there, pinned and configured" wasn't.
In my experience the months required to get a handle on Nix is not worth the benefit(which is shakey in my opinion) compared to competing technologies. We don't have to agree, but that's my take...
