I have to admit this sounds very funny to me.Not to be pedantic but I am able to use my iPad 2. Hence it is usable. Maybe not likeable useable, but useable.
You are saying it again. I did not put words in your mouth. “But ios 16 for all of the features is unexpectedly good“Where you are using the word “I” in the last paragraph above you are referring to feliapple. Because stop trolling me and putting word in my mouth: let me be clear: my Xs max and iPad do not exhibit whatever slowdown, performance degradation, battery life you speak of. There is no, little, within statistical normalities, impact to my devices which includes my new battery max and my iPad. There is nothing wrong with the option of getting more functionality for less battery life eg watching YouTube PIP while surfing the web. Which you can’t do on iOS 12. I can have more fun on my phone per watt hour of battery.
“There is nothing wrong with the option of getting more functionality for less battery life”
Like I have long stated, there is indeed nothing wrong with you trading functionality, features, and security for battery life. But that trade-off exists.
“I can have more fun on my phone per watt hour of battery.” True, but, like you said, you’re buying that with runtime. Which has been my whole point from the beginning.