I get the sense, at the end of this chapter, that this is a treatise in how to respond as a Christian during times of war. Of all the details that could have be included, the chapter ends making this point:
And now the number of prisoners who were taken exceeded more than the number of those who had been slain, yea, more than those who had been slain on both sides.vs. 40
Those that remained were more than those that had perished on both sides of the fight. That is a metric — a statistic, if you will, that was proof to Moroni (and those in his forces) of their success in stratagem. The fewer people who’s lives were spared, that they didn’t end their trial of probation prematurely, the better.