Chokes as opposed to resistors in the power supply do result in less ripple, but for me that's not the main attraction. Power supplies on bottlehead gear are plenty quiet as designed. With chokes, you can use lower value caps to get the same smoothing, which makes putting a film cap in the last position feasible. Just about any film cap will have lower ESR than the best electrolytics, and that's where I think much of the sonic benefit comes from.