I think that may be more for pro audio or outside stuff. Horns are used to create a wider angle dispersion pattern, so it just depends on the application. I'd love to see 12" deep door panels to fit that contraption in there LOL. I think it would be terribly peaky in a car.
I wonder if it's actually tuned? The length of that front part will tune a mid range, looks like those front small triangles are ports for the rear wave. So this may have some effect like a series 6th order. It's an interesting design, for sure.