I don't agree. For example Pebble is compatible with several apps and promotes runkeeper, but it's just bull shit:
instead of doing any activity you spend your time in front of a frozen screen.
This never appens with Run.GPS but the missing data in my pebble is frustrating :(
Up to now this did not make too much sense for us since all smartwatch vendors provided their own APIs and SDKs. I think this will change with Android Wear and we'll be able to provide a smartwatch interface in the not too far future.
It would be really nice if we can use a smartwatch in combination with the Android software; for instance to monitor heartrate during a training or to start a new lap with one click.
See also http://www.gps-sport.net/forums/thread/2421-0/