Comment by Jhsto

Speaking from the viewpoint of a whole operating system images, the main challenge is that while Nix allows you to create ephemeral environments, many people (myself included) have various hard-coded paths for mounting hard drives. If you want something to be shareable, you have to create a workflow in which the user environment is activated interactively after a tty session is acquired. Same goes for any system services that need persistence -- these have to be configured to be activated at runtime. It's a lot of work for a party-trick. It's probably possible to configure the system such that the log-in needs a FIDO2 key which is also used for LUKS drives, which would be similar to how macOS handles log-ins. But abstracting this such the login works on every machine possible suddenly requires filesystems to be networked, and so on.

That being said, we used NixOS images to boot several Windows PCs of my friends into RAM to play Halo 3 multiplayer split-screen. Most of my friends were mainly confused why they could play with any gamepad they had in their shelf. They also left the event with no permanent changes to their PCs.