Stow your (up to) 18" long by 1.5" high keyboard underneath and use it's USB-port-equipped shelf to hold and plug in your necessary desktop knickknacks; like a mouse, flash drive or digital camera. And with the aluminum it's obviously a perfect fit for Mac.
It's a cool design but it's part of an even cooler idea: It's posted on the Quirky community site. If you're not familiar, that means that a young budding designer (and his collaborators) designed this as a concept. If enough people commit to ordering the product, it will get manufactured and shipped out. No consumers are charged for anything until the design goes into the manufacturing phase.