A lot of stuff showing its folding allowing you to "use it as a bedtime clock" - have apple done any kind if battery use trickery to make this a non-battery-draining thing to do? Or maybe I'm overestimating how much battery a screen uses? (I'd have thought a lot)
This feature is well thought out in terms of battery use, because nobody is going to ever use their phone as a "bedtime clock"
Work smarter, not harder
iPhone Pros have sported an always-on display for years now. It uses the OLED display at low brightness and refresh rates to preserve battery life while showing you the time etc. So I'm guessing this is using that same tech.