It's a very complex subject and I know too much about it to make any statements about it without seeing some decent literature or experimental data. So this is conjecture. I suspect the damping properties of carbon relative to comfort are mostly marketing. Note that Spesh used to have elastomer elements in their carbon frames and have moved towards suspension without ever admitting the old way was mostly just marketing. This suggests to me that the thing people find bothersome is hitting bumps, including small ones like chip seal that are experienced at high frequency.