This maybe an old feature but I just discovered it. iPhone 6 running iOS Beta 2 10.3 (14E5239e) and watch OS Beta 3.2 (14V5214d). iPhone off in dress shirt pocket with camera sticking out. I open watch camera app from dock and I am allowed to open camera app on the locked off iPhone to take a picture and having the ability to zoom the camera lens. What a useful application, not the pocket picture taking but the ability to open the camera app from a locked iPhone.