I don't understand all the negativity. That said I did like the comparison with a Ducati and a Norton here though.
The Curl is a remarkable frame design structuraly, esthetically and functionally. Is it better than other bikes? Certainly. Does it replace other bikes? Perhaps yes, perhaps no.
I do agree that price is complicating. It's not the bikes fault. Mostly instead the market's inconsistancy. In many categories it would not be a high price, but in folding bikes it unfortunately is. Perhaps the market will change. There are indeed many aspects in the design that set it apart from a $600 bike.