Damper springs are meant to smooth out torsional engine vibrations. While they do a pretty good job in accomplishing this task, they can and do fail after high hours of use, as the springs usually end up beating out the pockets where the springs ride. Once that happens, they fall out and jam up the clutch to the point where it won't release.
Unless you're using this tractor hard all day every day, I wouldn't worry too much about the lack of torsional vibration reduction. It's nice to have, but not an absolute necessity.