What sizes of kite systems are we talking about?
There are small hobby uses; e.g. a single-line kite where someone wants to generate electricity up in the kite to run night lights on the kite without batteries. Then there are grand electric-grid-supplier kite systems in mind that may generate electricity to supply the needs of millions of homes. Projects are aiming to have the cost of the electricity be competitive with other alternatives for particular applications. So, there are suspected applications in hobby, military, and large-scale societal energy generation. Niche uses will be in the tiny kite system as well as extremely large kite systems. Air kites that use the wind, and water kites that use the flow of water--are the main players.