I think if you put the iPhone on a ratio scale like you do with TV you end up with a weird number...like 3:2 compared to the traditional 4:3 .
You end up with black bars on the sides when watching 4:3 shows but they are really almost not even there. Slim.
Same thing with wide screen formatted movies. if you double tap so that the entire width is visible you end up with black bars on the top and bottom but very minimal.
I think Apple purposely chose a ratio that's sort of in between standard 4:3 and widescreen 16:9 to not upset anyone who are die hard fans of either widescreen or standard.
There seems to be a divide between those persons who prefer 4:3 or 16:9 like screens:
• I prefer 4:3 simply because Id rather watch a huge screen and could care less for how far left or right the panoramic background spans.
• Then you have those persons who are completely OK with only viewing 2 inches x 6 inches of a perfectly good 6" x 6" screen (which makes noo sense to me) putting to waste all the space on the top and bottom with black bars simply because the panoramic wide screen is part of the artistic filming err something. I can't really say why, i'm not on that side of the argument
I watch Friends on my iPhone, and I make it fill up the screen. The amount of image that I lose on the top and bottom is never enough to even graze the top of a head or cut off anything crucial on the bottom, and it makes it look more cinematic.