I'll bet it's a necessity when bending aluminum. Otherwise the bar would have to be more sharply kinked where the downward curve cuts in towards the stem. Rivendell's website says that's the reason why Nitto Noodles are bent like that. On wider bars the curve is supposed to offer ergonomic benefits, but it's hard to get that wide on bars like those where the drops flare out. So you're left with the wrist twist unless you want super wide rando bars.