Went from an iPhone 12 Pro to a 13 mini for the purpose of being one handed use. It’s great to have a phone that is light, fits in the pocket easily and can be used with a single hand. The battery life you mention is due to Apple not including a higher density/capacity one. It’s not all about physical space. Had Apple put a high density/capacity battery the phone would be a little heavier (don’t mind) and would have similar battery life as the 6.1” version. There may have been a fear that people would purchase the mini due to lower entry cost of a high end phone had the difference be screen/phone size. I find the mini sits well in my hands for prolonged use and it charges fast.
Unintended consequences; battery drains faster with 5G use which means less phone usage (can be a good thing due to less screen time), phone charges fast due to smaller battery, when travelling I always have a power bank even when I had the 12 Pro. Actually the 13 mini lasts me as long as my 12 Pro.
As you can tell it’s Apple’s decision to include a lower capacity/density battery in the mini. I suspect it’s to nudge people to a larger sized phone to reduce machine tooling costs.
