I've rode dave kerr's rockman slate xl, and it has bars the same angle as Carthys more or less. the bar angle is stupid on the flat, and does hurt your wrists like hell. however, on the back wheel, you are nearly vertical and your hands are in the perfect place for big gaps. you can also get a load more power into gaps and stuff. it makes sense, but unless you are a massively skilled rider who can do real big stuff, you won't benefit from it in my mind. Carthy and dave are world class UCI level riders, and that's what works for them