You make some good points, however I'm referring specifically to an evacuation situation on the ground due to fire, explosion, sinking or imminent destruction of the aircraft, where disembarking as soon as humanly possible is preferred.
Sure. I'm pointing out how enabling your scenario may have negative consequences for other scenarios, and the difficulty of determining if it's justifiable.
In certain other emergencies however, routine disembarkation is the preferred way to deboard the plane.