As we've stated a few times before, when choosing an industry to make a drone for, you have to balance the size of the market (demand), with how much money they have to spend (cost), and how easy it will be for you to fill that demand (supply).
One of the industries that is extremely popular is golf. Every year, consumers literally spend billions of dollars on golf equipment and accessories. One thing golfers go nuts about is the new technology to help their game. Sounds pretty much perfect, right?
So, where can a drone fit in? A multicopter to fly down the fairway and check the layout? Maybe, but if the golfer has played that course before, why would they need it? They wouldn't. Ok, that's a bad idea. What about a submarine drone to look for a golf ball that went into the water hazard? Not a terrible idea, but there are probably so many balls sitting at the bottom of a water hazard that finding your own ball may prove impossibly difficult. And who wants to keep...