I agree with you on the bar length thing Brian, but limbing evergreens is different than limbing hardwoods. You are not walking the trunk and knocking off branches. You are often standing on a branch reaching out and over your head to cut another branch. They are often all over the place, often very hard to reach. A light saw will keep you working longer.
When ever possible, I like to cut them to length right off the tree, no use moving it more often than you have to, and I would rather cut it in the air than on the ground.