Hey, I think it's overpriced as well. No arguing there.
But depends what you're using it for too. Someone in the city might like the ultrasmall dimensions/maneuverability , attention, Benz dealership experience, convertible top, awesome mileage, and somewhat exclusivity (since not many people will spring for one).
I know my mom loves the thing. Never seen her so excited over a car, much less tell others about it so enthusiastically. Mind you, purely from outward appearances: "It's sooooooooooooo cuteeee"! And it is rather unique. It's not just that it's overpriced, it's that it doesn't offer enough space or utility for many people, so it will remain pretty much a promo, city, chic, or environmentalist's car. That's a big part of it's appeal right there.
But for my $30G, it's definitely not worth it - convertible or not. At $18G for what I wanted versus $21.5G, I'd probably be keeping my order for one.
Hmmmm... wonder if I could make a quick buck in Auto Trader?..