So, I bought this intending to use it as it is meant to, and it has done a good job. However, it also serves a secondary, yet unintentional function.
Listening to music, I took the cover off, as it is slightly frustrating to use for extended periods of time because of the larger amount of effort needed to push the keys down, and realised that the amount of treble I could hear from the speakers had...well, trebled.
Putting the cover back on, I could no longer hear as much treble, which is brilliant for a Mac user, because, as you should all know, the Macbook Pro speakers are incredibly tinny, and if you're running off them, the cover makes them quite a bit better.
Oh, and it's quite good for keeping the keyboard clean too.