I reckon a "drive 1-2kms on a designed route and park" capability alone would be pretty useful for city planning. Imagine if instead of needing to put parking spaces everywhere, planners could just plan robust routes that any car could use to go and park itself. You could could achieve it today by telling people to just walk from a car garage, but the uproar whenever there isn't enough parking right next to the exact place they want to stop is too huge for it to ever happen