Pixelphobe people are odd. They always come in with impassioned arguments about more pixels can't bee seen, the strain on the OS is too much, people watch from long distances..
And they are always wrong. 1080 is better to watch than 720, 24mp cameras are better than 6mp ones, retina iPad Minis will blow away the current one. Same with the phone. More is better.
But there's overkill.
IE - most people who are only sharing photos online don't need 24mp. A 3.2mp is MORE than enough.
And it's not about MP - it's about the sensor size and quality. And the lens. MP means more when you are cropping and still want a full sized image and or you're doing HUGE reprints. And I mean huge as in banners/billboards, etc.
The odds in you being able to differentiate 720p vs 1080p on a 4" screen is nearly if not completely impossible.