This is an interesting idea for roads with quite a few lanes, like this 6-lane example. If there are 3 thru lanes in each approach to the intersection, and only one left turn lane, then you only need to use one of the three lanes leaving the intersection during left-turn phases. We can make use of the two remaining lanes in this case, to temporarily house the left-turn traffic. It's a more efficient use of space, if we can get drivers to understand what the heck is going on, and if the signals are phased in the right sequence.
My problem is-- doesn't this limit the movements that can be allowed during a signal phase? A 4-way intersection needs 4 phases to permit all possible movements. If the contraflow intersection necessitates any phases limiting the procession of traffic to one side at a time, whether left turn or straight, that increases the number of phases, and therefore, wait times. More wait times = less efficiency. And you have to clear one direction's left turn lanes before the opposite approach's straight movement. Idk