I have a CF gortex bivy, olive green, and thinking about giving it to my sister to make some sort of long 'snowy river' type coat or cape. Might still work over my sleeping bag under a small tarp. Anyhow, at 2 pounds for approx 60"x80" the heavy gortex is 8.6oz per square yard, which seems comparable to the packlite maybe. I like the idea of a light full length coat or cape. It does do the waterpoof/breathable thing fairly well. It would be nice if it could serve as a bivy and a coat or cape.

True about no warmth. Sometimes it is better to go with more wool and fleece and a lighter shell, even is the shell doesn't perform as well. Especially at very cold temperatures where the shell tends to ice up anyways, a light one might be just as good once iced up. Can't always count on that though. Then there is cold rain, windy cold rain, windy cold freezing rain, that sort of thing. As long as you aren't taking it out of your wool/fleece a better performing shell is worth a little extra weight, if it works as it should. So I've learned to like the CF bivy material and wonder about it as a coat or cape.