Kites and Kite Flying
Kites have been around for long centuries, and have served many purposes from simple fun to military recon. Authors have long had an affinity for kites and kite flying. A famous character from a Dickens novel, "David Copperfield", Mr. Dick loved to fly kites and it relieved his mind greatly. Watching a gently flying kite can certainly be therapeutic and building them is a fun hobby. Considering the fun and educational benefits of kite flying that the seaside is not crowded with them on any breezy day.
Yes, there are many uses for kites and a huge array of kite designs, from the traditional diamonds and deltas all the way up to stunt kites. Stunt Kites are those two stringed - controllable kites that you will occasionally see out at a park on a windy day. They are a step up from the standard kite because the flyer, within a certain wind-envelope has a considerable amount of discretion about where and how the kite will move. It is called a stunt kite for a reason, many aerial maneuvers can be performed with a stunt kite.
Another innovation in recreational kite flying is kite surfing. Here a kite or parasail is used to pull a person on a surfing board. Kite surfers should be careful about wind direction and time travelled over water to ensure that they do not end up so far from shore that getting back might be a problem. (Bring along a compass, or better yet a waterproof GPS device.)
Historically, kite flying spawned the Wright Brothers' attempts at heavier than air flight. It has long been seen as a simple way to get something into the air, including weather instruments and observation devices. Some designs have been around for centuries, others spawn innovation after kite innovation and still remain true to their original designer.
Kites do, indeed, server many useful purposes and are a great hobby for millions around the world.