I equate to hanging out my down bag in the morning when it's 0F to the discipline needed to remove clothing as you hike to keep your layers from sweating out. It's just one more chore that needs to be done on winter trips longer than 2 or 3 days. A dry bag is a happy bag.
Sometimes I use my bear line to hang out the bag, other times just a handy tree limb.
This pic shows what -10F looks like atop a 5,000 foot North Carolina mountain in Jan. 2009. Hang your bags, boys. This time I'm using the bear line.