In fact, I was surprised to learn that many did not know that the Galaxy S4, for example, shipped set on 9.6 megapixels. That is why, CellPhonius's own Danny Alvarez put out a video detailing the "secret setting", while not so much a secret as a hidden setting, since the phone advertises its 13MP powers.
I love the way fellow Android enthusiast, (I would call him an Androcrat) Christian put it:
"The point here is at 13mp (4:3) you're getting the same width but less height then 9.6mp (16:9). So at first glance 9.6 will seem better because it better fits your S4's screen as it will your HDTV. The catch would be that you could still shoot your photos in the 13mp mode and get more scenery (like the sky and ground) and still later crop it to the exact same photo you would have got in the 9.6mp mode. You shoot your photos in 9.6mp originally and there is no adding what is cropped back. One more pro shooting 13mp photos is most printed photos are in the 4:3 ratio. The type that go in frames.
If you had shot in 9.6mp originally not only would you be cropping scenery right off the bat from the top and the bottom of the photo, but if you wanted a print that'll fit a standard frame, you'd then have to crop even more of the photo on the sides to get it back to 4:3.
The only cons would be that 13mp shooting is going to take up slightly more space per photo and not fit your phones screen fully unless cropped or zoomed in. The option is totally a matter of option but I would take the latter. We only live once and I don't want to miss a thing! Hope this helps all those trying to decide which mode they should use!" - credit: AndroidCentral
Another Android user said:
"I'd go for the 4:3 aspect ratio because it captures more of the image. This thing takes great pictures, but the area that is covered is dismal; you have to stand very far from a scene to get it all into the picture. 16:9 makes that even worse as it 'zooms in', and you'd have to stand even farther away." -credit: AndroidCentral
When all is said and done, it is all about preference. Samsung might have assumed that you prefer the snappier setting at 9.6, given the complexity and size of their skin which gives you the Galaxy experience of Android. To many, thought, capturing more information, thus, clearer pictures is key to finally letting go of their point-and-shoot cameras, allowing their new smartphone take their place.