At the risk of sounding incredibly sophomoric, I suspect they're just laid on the frets in the patterns normally given in scale pattern diagrams and that way they're on the fretboard itself? You don't have to keep looking from a book to the fretboard and back? Probably "repositionable" so you can map out your "scale of choice" for the day? (the "black dots")
Seems incredibly cumbersome to me though, and possibly a big PITA to play on.
But maybe half the "battle" is that while you're actually laying 'em out you're reinforcing your memory of what the patterns are for given scales anyway?
Don't wanna knock it, could be just the ticket for some folks.
:wink: