I think, based on the small subset of threads I have sampled by a convenience procedure, that not displaying minute-by-minute comment scores avoids the cognitive illusion human beings suffer from called anchoring bias

http://en.wikipedia.org/wiki/Anchoring

http://www.sciencedaily.com/articles/a/anchoring.htm

and helps readers focus on the inherent worth of a comment. That's my general observation from seeing which comments are floating up or down in threads and which comments are graying out.