The concept of earning badges and achievements in a game adds an extra layer of fun and competition in completing the game. I have played several games over again just to achieve new badges or achievements for collection value. This concept has been in the entertainment sector for decades but seeing it cross over into educational settings would help improve engagement with learners and their content.
Although admittedly not the competitive sort, I can appreciate how friendly competition against others in a social context can lead to socializing, relationship-building and teamwork. I can definitely relate to the way the playful design of the badging system lends itself to sustained engagement.