I am part of a team that maintains extensive collection of R and Python packages for a large (hundreds) community of data scientists so that they don’t have to waste time fighting the compatibility issues. We build the closures (the “bundles”) on systems with multi-user nix setups but deploy them on systems where nix is installed in the single-user mode. That “admin” user is the only one who has write access to the nix store, the regular users don’t use nix at all.