I agree 100% with what 3*Bork has to say about bivy bags / "wind bags" and their use. Not everyone who goes into the Scandinavian wilderness has one, but most people who do that often will bring one.

My primary bivy bag is described here in the "PSK sharing centre" thread. I have no augmented this piece of equipment with the AMK bivy bag, but that I view as an expedient, one time use only emergency center. My big bag is usually with me except on trips where it is totally unwarranted.

While my bag's primary role is as emergency shelter, it is usually employed as a wind break. It is VERY nice to whip up a wind break in 120 seconds whenever you shall have lunch in somewhat sub-optimal weather.

My wife and I have had lunch inside my ("our?") bivy bag in snowy weather (somewhat intimate, but we weren't complaining), but otherwise I consider myself lucky that I never have had to use it as an emergency shelter.