I think that third party app development is crucial to wearables, simply because everyone seems to have their own ideas of what is important / useful to them.
Some want health monitors. Most want notifications. A big group likely would love little time-wasting games.
On the WIMM One which I often wore without also carrying a smartphone, I used a world clock (to check times in India and Hawaii for conf calls), timer app (for quick reminders), weather for various cities (for when my wife would ask), and oddly, a newsreader for CNN, Gizmodo, etc, to pass the time in waiting rooms.
Others, like you, will want golf apps. Someone else might want to be able to show off photos of their grandkids at any time. Many would want a list of next appointments.
Possible uses are as broad as with smartphones.
Next up: kid's smartwatches, with simpler apps for position monitoring, virtual fences, emergency notifications, parent-controlled timers for play times, and cute visual watchfaces telling them when to brush their teeth or go to bed.