My wife avoids using computers after work. Her phone is in essence, her surrogate for an iPad (which she used to love until she got her 4S), laptop and camera. For her, a 5" screen is a plus given her use case.

A few years ago, I also thought the 5" screens were silly, but that was before I had to start wearing reading glasses. I just upgraded my iPhone to an Android phone with a larger screen, and it's so much easier on my aging eyes.