This device does (well, conceptually) one thing: electronically turn sheet music. You simply tap the little foot pedal when you’re ready for the next page and that’s that.
Never having played an instrument, save for strumming along to a couple of Sleater-Kinney songs in the halcyon days of my youth, I don’t personally know how annoying it is to have to quickly turn the page as you’re playing scales or whatever.
And may I add, vertically aligned images have no place on the Internet. How awkward does that picture look? Any bigger and it’s do a number on your vertical scroll bar.