I am sure that someone buys them. What exactly do you mean by worth it? Do you mean, is OS X really worth enough to warrant buying someone's computer from them? Is Windows worth it, is Linux, OS/2?
What exactly are you looking for in a machine? That will dictate whether or not it is pricey. If by that you mean that they don't sell a $500 laptop like most everyone else... then tough noogies, the $1100 laptop that they sell is quite the performer (ok, not with games) in pretty much every regard.