The explanation on the Apple website for the iPhone(/touch) says that screen brightness might drop, signal might drop etc before it goes to this screen. Appare

The explanation on the Apple website for the iPhone(/touch) says that screen brightness might drop, signal might drop etc before it goes to this screen. Apparently Apple thought well ahead that it might be best if their device regulates its temperature rather than overheat and shut off. I'm actually exceptionally surprised by this, kudos apple.