Why are Superbirds worth so much?

What ever won at Daytona on Sunday would sell in numbers on Monday.
Nascar and Richard Petty got those cars off the showroom floor. in the following years these cars had low trade in value because used car lots couldn't move them and didn't want them. Funny thing was just about every customer would walk around the thing and get a good look at it even though they wouldn't be caught dead in it. Used car salesmen compared it to the bearded lady or similar sideshow attraction and joked about charging people a quarter to look at it. So the aerodynamics were removed, damaged or not, to make a more appealing model.
I should answer your question. The curiosity remains. If you want something to take to a carshow or cruise-in that will draw maximum attention, thats the one.