[junkyarddawg]

One aspect of the challenge every year is the diverse approaches to a solution. If we all thought the same way, we would all show up with the same robot and the competition would be extremely boring, especially to the noninvolved spectators.
No sport that I can think of survives without offence and defence. Just imagine football without defence. Each team takes turn going onto the field and running/passing the ball from one end to the other as fast as possible and the winner is determined by which team had the lowest average time. It would certainly not compete against sports with offence/defence. The defence is really what drives the mix of plays in a sport. Even in chess, defence is extremely important. Offence/defence in a sport generates the most diversity and requires the most strategy.