The killer argument in favor of the CoP (thanks to GKelly for keeping this front and center) is, I have come to believe, that figure skating is not just the top two skaters in the world battling it out for the gold medal. The scoring system must be useful and appropriate for all competitors at all levels, from 6-year-old Snow-plow Sam to adult recreational skaters and club competitors.
And at those levels (up to prejuvenile or open juvenile and adult silver), US competitions still use 6.0 scoring.
But the scores will mostly be in the 1s and 2s and no judge is thinking about the scores in terms of how far away they are from a perfect 6.0.
There isn't even really a firm meaning of, say, 2.0 that would apply the same in a Basic Skills freestyle event and adult bronze and prepreliminary. Judges would just pick two numbers approximately in that range to score the first skater and then mark the other skaters up or down from there.
The actual scores are just a means for judges to keep track of how they're ranking the skaters. Competitions at those levels use closed marking, so the skaters never get to see anything except the ordinals.