I agree that photoshop bevels have been overused in all manner of digital images and such, and that they are often used by inexperienced users who think it makes their creation look better just because. But I haven't used it on a whim, the skin itself uses the effect (which isn't as simple as a single bevel) to make them seem like they're stuck onto the screen, rather than displayed by it.
I guess I was aiming this skin at people who don't wont fancy interfaces and would rather have the simple and somewhat cute interface that this skin offers. To that effect I might make a pink version
as I think this would go down well on a girly desktop.