You're missing a few advantages: * Automatic ability to integrate into environments designed for humans. Think doorknobs, ladders etc. * All the advantages of

You're missing a few advantages: * Automatic ability to integrate into environments designed for humans. Think doorknobs, ladders etc. * All the advantages of legged locomotion over wheels. * Once you have legged locomotion down you might as well do it on two legs and add some arms, and voila you have a humanoid robots.