Also battery life, You can give a human a couple of sandwiches and they'll go all day, the robot probably needs a 20kg battery and still won't go more than 8 hours without charging. Its actually one of the kind of mindblowing things about organic systems, A whole human body runs on less power than just the control unit for one of these robots (assuming its similar to a mid range laptop) let alone the motors.

Expensive and impractical today, yes. But we would say the same of every man, woman, and child having a supercomputer with the entirety of human knowledge in their pocket fifty years ago.