I agree that it would be great for rental cars or people new to an area. Not sure why it has to be a robot, though. What if I wanted to make use of a variation of the technology that would aid walking, biking and using public transit? I wouldn't want to lug it around. Perhaps they could add legs and it could walk around with you and carry your stuff. That would be innovative.
MIT's AIDA Robot Is Going To Be The Ultimate Backseat Driver