Another aspect is that the Nix experience varies widely between languages, in part because of different levels of support for different languages but also becau

Another aspect is that the Nix experience varies widely between languages, in part because of different levels of support for different languages but also because different languages’ build and runtime systems vary with respect to how easily they map to Nix. So your friend who heartily recommends Nix might have had a decent experience with his Haskell projects, but you and I working in the trenches with Python or Ruby are having a miserable time and everyone who told us Nix was great just kind of shrugs and chuckles as they tell us they don’t know how to solve our problems with Nix.