They appeal to people not the tech world. They are slower dumber phones than androids but androids arent advertised like an apple product is. If the public cared about possessor cores and ram and gigahertz then android would be more popular. But they dont so they go to the brand that says things are so easy to use. Same argument goes for mac vs pc
Even if you terminate phone service, you can still message, go on-line, down-load apps, Facebook, etc., with Wi-Fi. All you've lost is phone service and phone messaging to people that use other than AT&T.