Brian originally coded that for pyprocgame, and it works there too.
I (and others) use it for testing. It's wildly helpful when you can't make a shot or, in the case of testing against Visual pinball tables, can't take off the glass for some reason.
There's a thread on pinballcontrollers about it, here:
http://www.pinballcontrollers.com/forum/index.php?topic=983.0
Quoted from toyotaboy:I'm loving this video.. Seeing insert light matrix on a tablet real time, then in real time controlling the lighting manually from the tablet
» YouTube video