There's a thousand or so of them scattered around Europe which were the foundation of the company I work at, acting as IoT hubs to communicate with devices designed to alert insurance customers of floods, intrusion, and fire in their homes. We hadn't ever really planned to get into building our own hubs, but the RPi ecosystem meant that when we were forced into that corner on short notice (thanks Smartthings for shutting down app approvals at the last minute) we were able to go from zero to working product in a matter of weeks!