According to the latest information, the Google Pixel Watch 2 means that a single tap of the always-on display (AOD) will immediately launch a complication.
Google Pixel Watch 2 AOD complication
If the always-on display is active on the original Pixel Watch (running Wear OS 3.5), a single tap disables the AOD/activates the screen fully, and then you can tap on the desired complication or app shortcut.
Google Pixel Watch 2 with Wear OS 4, you can tap a complication on the AOD, and it will instantly launch. If you haven’t been using your watch for a moment, it does take a second from tapping before the screen wakes and the app launches.
