Maddslacker….Being as i ride a hardtail, the very noticable difference for me was the vibration dampening. When riding with my aluminum bars my hands would go numb after a while even after i put on Ergon grips. Since i changed to carbon it has helped alot. I don’t think i need to explain the benefit of a carbon seatpost on a hardtail.
These benefits might not be as noticable on a FS bike. I don’t know. For me it made a difference.