I'd be interested to hear more about how you're using NixOS if it isn't something you've already written about. My guess is that you're mostly leveraging the declarative configuration and immutability for internal infrastructure use. What I'd love to see would be consumer devices using NixOS, allowing updates (especially security patches) to be deployed to endpoints without too much fear that it will brick something. I think that would allow companies to more inexpensively maintain their IoT devices throughout their lifetime. I imagine a device where it could automatically revert to the last working generation if a new config fails for some reason.