Chill, dude. As someone pointed out earlier, it all depends on what you mean by "efficiency."Ok, so efficiency is not a concern for you. This wasn’t a question of “your favorite fin for your preferred diving style or conditions”.
Your definition is not everybody's.
If you want to focus solely on mechanical efficiency of converting leg motions to forward movement, using a flutter kick, fine. But others might want to include ease of packing and traveling with the fins, weight, use in more situations than just going forward in an unobstructed area, cost, even color for heaven's sake.