It seems like a team building exercise. Everyone sees how everyone else works, and helps them grow. The 'client' is there to provide feature requests to see how

It seems like a team building exercise. Everyone sees how everyone else works, and helps them grow. The 'client' is there to provide feature requests to see how whoever's on the hot-seat implements those and responds to changes/criticisms. Note: In this scenario the client might just be a senior programmer, pretending.