Then what's the point? Don't get me wrong, I'm an overt Noctua loyalist, but I don't see the point of creating new products just to create new products. If the round version of this fan has exactly the same performance characteristics as the square version, and is the same color scheme, and doesn't have any other purpose to it other than being an additional model to offer, then it makes zero sense. This is not something Noctua is known for doing. They invest a great deal of time into engineering and developing new products and it baffles me that they'd do that for a product that doesn't offer something, anything, new.
Additionally, seems like time that would have been better spent on actually developing something that was new, or improved. Have we come to the point where we feel that's not possible anymore so now we have to be like EVGA (Power supplies) and create 50 different models of something simply to have a larger product stack?