In-Session Apps
Hidden within the watchOS 6 settings, there’s also an option to choose which apps will stay live on your Apple Watch screen when “in session.” For example, when in the middle of a workout or on a call, listening to music, or navigating in Maps.
When switched on, these apps will “take over” the watch face when you’re in the middle of a session in them, however only one of them actually takes advantage of the always-on display: Workout. During a workout activity, it will remain on-screen, even when in standby mode, although like the second hand on the analog watch faces, when you lower your wrist the seconds counter on the timer will be hidden in order to preserve battery life. This is due to the new display in the Series 5 which only refreshes once per minute when in standby mode.
Other in-session apps, when enabled, will still remain active on the screen in the background when in standby mode, but will be blurred out with a digital clock overlay shown instead, returning when you raise your wrist. This works much like it did with prior Apple Watch models. It’s also worth mentioning that there are no APIs in watchOS 6 for third-party apps to take advantage of the always-on display, so for now Workout is the only one that will get this kind of special treatment.