My concern is the absorbant inner lining. If I am wet and I get in the bag to reduce hypothermia, I just filled my bag with water. Instead of it pooling in the bottom of the bag and allowing me to pour it out, it is absorbed in the lining and staying wet.
Sounds like wearing a diaper. Not sure if that is what I want.

I like the arms so you can still do things while insulating your body.