This is the type of design I love to see. It's not just a composition but a fully working prototype. I feel like you learn so much more when you actually build out a system. The summary is key, because when I built my first Watch app back in December, I realized that a lot of designs I saw online for conceptual applications were almost impossible given what is available in the SDK.
Also want to thank your team for open sourcing the project and spreading the knowledge!
Edit: Just submitted a PR to fix this project so that it works with the latest Xcode.
When I saw the title I rolled my eyes expecting to see about two hours of Photoshop work combining two popular brands for attention.
Talk about a pleasant surprise. They actually prototyped it, and open sourced it. This is pretty damn cool.
i can't imagine a reason for this to be on a watch, other than cool factor.
Locking and unlocking the car from your wrist would be pretty convenient.
It is worth it. If you have a zipcar membership you can use the app to sound the horn - very handy in locating your vehicle.