I expect it takes quite a bit more energy and machinery to make the case by machining an extrusion vs. casting it. The very tight dimensional tolerances are unnecessary for something like a laptop that will be replaced in a couple years....but stuff like that does seem to appeal to the targeted market segment (mostly folks who are not mechanical engineers, and have sizeable disposable income).
It's a work of art, for sure!
btw, thanks for the link to the video