Too Long; Didn't Read
Engineers who design robots have no holistic idea of how the robot will actually look in real life, in full-scale in their lab, workplace, etc. by looking at a 3D model on a 2D computer screen. Engineers must take into account the orientation of every part, measurement of each side and angle, the location of the part in terms of the whole assembly, surfaces that should meet vs not, appropriate torque required for any screws. This is super time-consuming and is prone to multiple errors along the way. This allows you to get a better perspective and design the robot with the perspective of its surroundings.