I've heard that reasoning given, but I'm not convinced that makes much of a difference. Unless you're watching in one of those giant theatres where the screen w

I've heard that reasoning given, but I'm not convinced that makes much of a difference. Unless you're watching in one of those giant theatres where the screen wraps around the edges of the walls, the screen you're viewing something on probably isn't taking up your entire field of view. You're usually moving your eyes around to look at different points of the screen anyway, and if you can comfortably see all parts of a vertical screen it shouldn't make that much of a difference. Furthermore, if you close one eye it's not like it balances out to make horizontal and vertical video equal, nullifying the reasons I mentioned. I think the issue is just in capturing the content. There's more useful things in the real world you can capture with a wide view than a vertical one.