It's rarely the case that you want to look at a camera or a phone photo at 100% zoom unless you're cropping a smaller image out of a larger one. Of course, sometimes it's useful for things like reading text, but that's limited by the lens and focus abilities as much as the sensor resolution.

You'd be surprised how little megapixels are just fine for putting up on a wall or billboard. It's all about how far away the viewer is.