Psychologically because it's life-like (uncanny valley). Practically, because legs are superior to wheels when it comes to pursue a human target. It may be sup

Psychologically because it's life-like (uncanny valley). Practically, because legs are superior to wheels when it comes to pursue a human target. It may be superior to flying as well indoor, to open doors, etc. And then there is the energy expenditure and additional mass constraint when airborne. Research on legged robots is not just for 'fun', it's because they are better at going through obstacles and rough terrain than wheeled vehicles.