Robot vs Advanced robot
Someone can write a robot just for fun. Why there are races on bicycle, when you could also ride a motorbike. Why we have code-restricted classes. Mind you, the best robot (kawigi.robot.Girl) is not easy to defeat, especially in melee. Most school competitions I know of use Robots, as it probably easier to check and control the code and its behaviour, and to prevent 'lending' code from good bots out here. For me, writing a robot is more difficult than writing an advanced robot, because it is hard to wrap my mind around what to do when and so on.