[Update 9/24/2019: This is still the default behavior two years later, and it can be especially frustrating on the new Apple Watch Series 5.
The new Apple Watch has an always-on display that shows your watch face and the Workout app even when your wrist isn’t raised, but all other apps are blurred out with a digital clock in the corner. That includes the Now Playing screen even if audio is playing from your iPhone, preventing your watch face from showing at a glance.
Read below for instructions on disabling the default auto-launch audio apps feature.]
watchOS 4 introduced a new default behavior to auto-launch audio apps when you wake the screen while playing audio on your Apple Watch or iPhone.
Auto-launching Now Playing can be useful when you’re playing music from the watch or a podcast from the phone for example. Instant access to play/pause and seek controls on the watch screen and the ability to spin the Digital Crown to adjust volume is really great when using AirPods since they lack physical controls. It’s sort of like the Now Playing card on the iPhone lock screen.
But this behavior isn’t always ideal on the Apple Watch. Luckily there’s a simple way to turn it off.