> people seem to be more realistic about the variance in actual delivered points per sprint, as opposed to when you try to measure things in hours or days
Okay I think I'm with you. In my team, the PM pre-calculates the number of available days in the sprint per developer before taking any estimates, factoring in planned holidays and estimates of sickness and meeting time, and adjusting for seniority. I guess points are kind of a crude way of doing the same thing.