Seems to me, any case where a robot needs to navigate an environment built for able bodied humans. Quadrupeds get close, but even they will encounter spaces we have organized for ourselves that they can't navigate in. An immediately useful and saleable use case would be a two legged robotic exoskeleton to replace wheelchairs or mobility scooters. More than replace, being able to perform actions like kneeling down to do gardening or play with kids. Or why not go superhuman and have extendible legs letting you reach the top shelf at the supermarket. Give the robot an opaque skin with open able flaps and the operator could use a regular lavatory for a bit more human dignity.