Gestural interfaces are highly cinematic, rich with action and graphical possibilities. Additionally, they fit the stories of remote interactions that are becoming more and more relevant in the real world as remote technologies evolve.
Games are highly dynamic experiences. The flow of events changes from moment to moment, and each decision a player makes can lead to a multiplicity of outcomes. Most games are also programmed with an element of randomness, so a player never has quite the same experience twice. Multiplayer games throw even more unpredictability into the mix.