I know many people that have no use for NFC, Qi charging or SD card. These people do not know that these features exist and moreover, they do not care. They do care about pictures, and having/not having a dedicated camera button can make a buy/no buy decision for these people. It's definitely possible to use a phone without it, of course, but the added convenience can be very important to some people.
Point is, different features appeal to different people to different degress. Me, for example - I really do not care about the camera - for it's main purposes, Facebook/Insta/Snapchat uploads, it performs very adequately on my Nexus 5. But I do care about NFC, HDMI Out and Chromecast capabilities.