There are times when the very things that make something a bad choice also make it a good choice. Granted, a single action is slow to fire and even slower to reload, but if a fellow knows he has only 5 or 6 shots to get all the work done, he will likely put more concentration and effort into seeing that each bullet goes where it is intended and will do the most good.
Give the same fellow a 16 shot automatic and a belt full of extra magazines and most likely he won't concentrate nearly as much on where each shot goes unless he has had it burned into his brain via training. Otherwise it is most likely spray and pray with any auto and lots of rounds.