It's battery life.

I was an iPhone 13 mini user for the last few years. I would buy a refurbished one off Amazon whenever my current one broke. I really prefer the smaller screen size.

Recently, I broke my phone again and my wife happened to have a larger iPhone laying around unused (through some accident of e-commerce). I felt weird buying a new phone when we had a perfectly good one laying around, so I decided to give it a shot.

I don't watch any video on my phone and most of my screentime is Kindle and Safari. My screentime is only like 2-3hrs per day. And yet, I still found myself chronically running out of batteries on the 13 mini. I actually now would prefer to keep my new annoyingly large 16e just to not have the battery anxiety.

(A hidden assumption in the above is that larger screens make more room for battery.)