When considering the quality of a design one of the things we focus on is the coupling between entities. Coupling is both necessary (you create a system’s behavior by coupling entities to each other for collaboration) and often problematic (excessive or illogical coupling produces unpredictable side effects when changes are made).
For Agile games, the Agile 2015 conference was a breakthrough moment. Not only was the first keynote about games, but the odds were good that you encountered a game in at least one of the sessions. Agile disrupts the old rules of software innovation; serious games are tools that help with this disruption. The fit is natural.