Split fins?
Agreed
I agree it is more efficient. However, I find a motorcycle hand mirror super useful for keeping track of my buddies behind me, swimming on my back towards a target, and also checking myself out as I always look so good! (kidding)
You're a zealot (kidding). Hey, it makes absolute sense for that.
It is a rare exception to see people swimming face down when shore diving around here. A few dive sites (like Edmonds Underwater Park) have long surface swims, but most don't as it is a good way to get run over by a boat.
Understood
It is useful for snorkeling!
In all seriousness, when diving OC, I have a collapsible one in a pocket.
In most places, I would say they don't need it. However, it isn't a bad thing to have for an emergency. Case in point. If I were left at sea and I had to swim to land, I sure as Hell woudln't want to swim on my back, but on my stomach. But 99% of the time I don't need one. But there are scenarios where one is absolutely useful. I think it is because snorkels are rammed down our throats as must haves that there is this reaction. As I could easily teach open water to students without one. However, given that on rare occasion they would benefit from them, I would be shortchanging them if I didn't teach them how to use them properly.
Some instructors will do the minimum of have them use a snorkel on their first open water dive and then get rid of them. I disagree with that. I think they should be taught to remove their snorkel, store it, dive, on ascent restore it.