In Germany Mercedes assumes all liability for these situations though (60kmh, highways, good visibility), so I don't see why Tesla couldn't do the same if they were just as confident in their system, but apparently they don't trust it enough for that. Instead they claim their system can do all these things on it's own, while the driver doesn't really benefit from it as they are still liable for everything it does and not even allowed to use their phone while driving, which is something you are allowed to do with the this new system from Mercedes.