Author addresses friction in NixOS's monolithic deployment model when managing multiple project repositories. Rather than redeploy entire system config for small changes, he leverages systemd-nspawn (lightweight container tool bundled with NixOS's systemd). Key insight: systemd-nspawn containers integrate seamlessly with the host—they register with systemd-machined, enabling full service tree visibility via `systemctl --recursive status`, including services inside containers. This approach enables lightweight, isolated project deployments without full system reconfigurations.