An Eos is not a cheap car even in its basic trim level, and whilst the Xenons arn't exactly essential, after you have them there's no going back to that dull yellowy light regular headlights give off. So what i'm saying is your already paying a high price even if you dont spec it up, so you may aswell have a few options to sex it up.
Plus, I think the Xenons clusters just look better anyway, with the main body of the light being reserved for the moving lenses and the side lights/indicators tucked in on the inside.
Finally its a great gadget to show your friends when you start up the car at night and the light beams move all around while they self adjust. Cool!!