We also have no idea what would happen if people use this device everyday, more than recommended, or for a longer period of time. It is driving change, eventually when that switch happens and change has occurred... then what.
I think this is the most interesting questions...I worry about over use and other confounding effects. If it slows down signal firing in your DCN, is it possible that people begin lagging in their speech? Imagine a world where you saw people speak but it was like a bad dub... and you were stuck that way.
Just a thought.