Exactly, I consider a lot of this kind of stuff as essentially price discrimination. It's not so much that the Merc is 15 times better than the Hyundai, as someone is willing to pay 15 times more to have it.
Think of economy and first class on a British Airways flight. There's no way BA would justify the massive price differential on the basis of a few free drinks, extra legroom and more attention from the staff. So is it worth it? Is it good value? Obviously some people think so. As with the expensive Merc, a large factor of this is probably the exclusivity set by the price (can't imagine first class seats would command the same price if they were distributed randomly around the plane).
Although it is said to have a lot of societal benefits (i.e. costs are weighted according to those who can afford to pay more), people usually balk at outright price discrimination (exact same good, different price depending who is buying). Hence the rise of premium branding!