I was running the lightshow for a medium sized nightclub and ended up building a custom React renderer that would declaratively control all of the lighting fixtures on the dance floor, strobes and smoke machines included. The entire show was controlled with various MIDI controllers (similar to Launchpads) which also had their button grid programmed using React.

It was suddenly very intuitive to build user interfaces on a button grid MIDI controller using standard React design patterns, not to mention the actual light shows being implemented as React components.