Matt Easton's schola gladiatoria youtube channel is mentioned elsewhere in the comments, and he's of the opinion that, in addition to the facets of unreliabilit

Matt Easton's schola gladiatoria youtube channel is mentioned elsewhere in the comments, and he's of the opinion that, in addition to the facets of unreliability and slow reloading (such that it was difficult to take a second shot if you missed), the lack of stopping power was another considerable factor towards the continued usefulness of swords, especially when considered in combination with a pistol (i.e., weapons used at close range). There are, from Easton's citations, many accounts from soldiers during the era of black powder that describe assailants who had been shot, and hit, in an eventually lethal area; however, they had enough left in them to carry through their attack, resulting in both the assailant and defender killed or injured. At close range, early pistols, even early revolvers, had decent offensive capability, but no defensive capability, in case your attack, even if it hit, did not stop or kill, so it was still handy to have a sword around to parry if need be.