The user experience of scrolling through and viewing lots of content on a 4" screen is honestly not great. Apple, being Apple, sees that as a problem. I consider it a feature because it's easier for me to break away from. Web browsers, youtube, mobile games etc. I don't write emails from my phone unless it's an emergency, but I like having a smartphone because it gives me the option if I need to.

A lot of those behaviors, I currently have trouble with at full-size computers. I can absentmindedly browse cat pictures on reddit for a couple of hours. But I have to sit down at my computer to do that, I can't do it comfortably on a 4" phone screen. And I like it that way.

Put that comfortable time-wasting computer in my pocket where it follows me everywhere and I'm about 99% certain that I'm have a problem.

I'd love to know if someone's studied this more rigorously.