If you go to the author’s bio page, she talks about the pedal indicator thing. To attached it to the harp, it requires 2 small holes drilled through the baseboard, and it can be removed.
I can see that this could be useful if the person playing is a visual learner, really likes gadgets, and wants to add another layer of crash and burn protection, but whether the unit really “saves” your performance or not, I don’t know.
So why not make it wireless? Not only would you not need to drill a hole in your harp, you could put it on the music stand, if you are using one (say mounted below the ledge, so that it wouldn’t interfere with page turning).