Sony announced a smart watch at MWC this year with some curious functionality. It displayed time, date etc, but also phone notifications, appointments, and could also act as a viewfinder for the camera on your phone.
Yo’s point of establishing a persona will help you a lot. It’s not really a watch, it’s just another display that happens to be attached to your wrist. Small displays aren’t great for input or creation, so what does your persona want to see when he-she looks at his-her wrist.