I think that's why it's relevant. It's likely the system can't make such a decision because its developers wanted to avoid having to deal with that can of worms. If this is the case the car may have insufficient options available to it in this type of situation. With a working "trolley function" it's possible the system could have noticed the obstacle then done some "moral math" with the chances the obstacle is a pedestrian and the odds of survival for the car's occupant(s) then chosen to drive off the road and crash into a ditch. Without this feature it's likely the system's only recourse is to stop and ask for help, which it may not have time to do.