Love the line, the funky interior, the super nice Maserati engine, and the flying carpet Citroen hydraulics, what a great car.
Some years ago it was considered as a weird car, some loved it, some not, but Citroen Hydraulics + Maserati engine was frightening without the internet. Finding a specialist for those super engineered components was a challenge. Now things are easier (doesn't mean easy ^^). If it wasn't always "cool", it was always special, now it's recognized as a fantastic car and everyone wants one.
The DS will always be special too, and imho über-cool. Love the 1963-1965 Buick Riviera, all Maseratis, american cars from 1938/1947 period, a RR Silver Shadow or Spirit... are they cool? I don't know, I think a RR in a funky colour (Green, Orange, etc) can be super cool too.
Imho, "Coolness" will change with fashion, but the content of the car, the line, the engine,the interior, the technology, that will always stay. There some fantastic ignored car. and they are ignored exactly because they are NOT cool... for the moment
François