i read recently somewhere that the southern forces cavalry favoured the pistol and were amused at the yankee cavalry's fondness for the sabre, southern use of cavalry as screening and reconnaissance as well as pursuit of running enemies was more effective than yankee sabre charges at organised masses of troops. actual battle between mounted units was rare.
maybe the yankees didn't get much chance to use the sabres if they were driven off by gunfire before they got in range. their use of repeating carbines was also laughed at as they were a difficult item to reload while on horseback, changing pre-loaded cylinders on revolvers was a tad easier, most southern horseman would carry several revolvers, and only officers might occasionally carry a sword. (also read the large D guard bowies were fairly well hated and not very useful, and were generally 'lost' pretty quickly so they didn't have to carry the ungainly things...)
unfortunately towards the end there were just too durn many yankees.
and some bright spark started supplying them with brass cartridges for their repeaters.