Very neat, I'll have to give this a go. `watch` is one I use daily at work for various reasons. Diff and history are the perfect natural progression here.
We would submit jobs to a cluster. That cluster would have a queue, and there was a command to see the state of all jobs (waiting, running, etc).
So I'd invoke it with the "watch" command so I can see the status of all my jobs and know when they've all done executing.
I'm sure there are hundreds of other uses.