I would have had zero doubt the fire and rescue services could deal with the hitch lock or the chassis very effectively.
Nevertheless, there could be situations where uncoupling is desirable and where they are not there to do so, nor you able to do so, or being able to find somebody your key.
I simply can't see on a journey, hitch locking offering any advantage, whilst it possibly becomes a safety or obstruction issue, better not being there.
No more complex than that IMO, then we don't lock all the car doors in transit, just in case we might need someone to help us, one day.