During the BA evacuation in Las Vegas, fourteen passengers suffered minor injuries. The ARFF were able to put out the fire before the aircraft was destroyed. In this case should the Captain have kept the passengers on board ? (Rethorical question)
Does the level of capability of the ARFF need to be considered in the decision ? In many countries I wouldn't trust the fire engines to arrive within the specified time or be able to extinguish a major fire once the got there. The SQ and BA incidents both occurred at major airports in first world countries. Narrow bodies go into airports which were never designed with the size of aircraft or volume of traffic currently being handled in mind.
Having the emergency services on standby for even a supposedly minor problem could save a critical minute or two compared to a cold start. I landed a turboprop with an engine shut down early one morning at an airport that handled scheduled A320/B737 operations. The airport was unmanned at my arrival time but ATC arranged for the local police to be in attendance just incase.