..If I understand correctly, the air makes a turn better than the heavier fuel. So even if the mixture was perfectly emulsified, the heavier fuel keeps going and partially separates from the lighter air that makes the turns through the intake ports. The rougher texture apparently helps to re-introduce the fuel into the airstream. There is more to it and I may have butchered the description, so give the webinar a view.
Understanding the Characteristics of Flow in Induction Systems | Production Engine Remanufacturers Association
