Perhaps related to notification preview options (i.e., only When Unlocked).What does "unlocked" have to do with it?
Speaking of hiding notification previews, it would greatly inhibit any benefit for me of AOD on iPhone.
I feel the opposite. The benefit of AOD on Watch seems to apply to very few cases, in my experience/perspective — namely activities/positions when your watch is frequently/constantly facing up. My Watch is fairly good at activating the display during any instance of turning my wrist upwards. Notwithstanding, YMMV.This ain't like the always on display of the Apple Watch, a device that actually has a reason to be always on since it's a watch.