Why isn't the megapixel war over?

In todays market camera's are a big issue for phones and sadly the most measured feature are the megapixels. In the eyes of the average consumer more megapixels equals to a better camera but that is utterly wrong. And here is why.

Camera specs

Camera's are a technical accomplishment and thus they have specs. But what is the most important? Most consumers think megapixels is actually the only way to measure a camera. But there's more. ISO, shutter speed, the available lens, aperture and I could go on, but I won't.
What do megapixels then really tell about the camera? Simply just one thing. It measures the size of the picture in total pixels. 1 megapixel = 1 000 000 pixels. That might seem like a lot, but it isn't. The HD TV's that most have at home have a resolution of 1920 x 1080 pixels. This is about 2 megapixels (1080 * 1920 = 2 073 600.

Sadly nowadays we somehow need phones to have as many megapixels as possible. Which, as most here probably know, a downside light every pixel gets. Yes this is the idea behind the HTC Ultrapixel camera.

Why do we need the pixels?

We need high pixelcount for one thing and one thing only. Viewing pictures on a high DPI surface, rather this is a screen or paper. The A4 paper is 210 mm x 297 mm (8,268 inch x 11,693 inch) and to get the same quality on those papers like we see in magazines we need a very high pixel count because printers print the papers with 300 DPI (avarage). This equals to 2480 x 3508 pixels (about 8.7 megapixels). On a smartphone the resolution takes care of the DPI. No more pixels can be shown on the screen then it's max resolution. On most flagships it is still 1080 x 1920, so no more then 2 megapixels. No matter how much megapixels your picture is, it won't show more then 2 megapixels at each given moment.


sizes are from gsmarena.com

And here's the kicker: Who prints their pictures taken by their phones? Surely some of you do, but does your sister? How about your mother? Or anyone close to you for that matter. For those that want to print, yes megapixels is good. For those who don't want to print: +2MP is not necessary!

Still we can do some neat stuff with more megapixels. The most obvious is of course cropping. You took a picture, don't like how far something is so you crop the picture to make it look bigger. Then there is underscaling which (if done correctly) reduces the noise in a picture and I'm sure there are still some brilliant idea's to come. But what is the highest resolution screen you have? I bet in most cases it's no more then 1920 x 1080.

So why are all the consumers still so obsessed with an extreme megapixel count when about 99% of the pictures taken with that camera won't ever be seen on a bigger canvas then 2 megapixel showing up in facebook and twitter?