According to the Snowpulse manual, once the bag is inflated it will slowly deflate over the next several minutes. So in THEORY it could provide some air, but more importantly maybe some space around your head. The space would be hugely important to help avoid or at least prolong the following scenario. Snow is about 70% air, meaning there is plenty of O2 to breathe. The problem is that when you exhale, the heat from your breath eventually forms an 'ice mask' around your head (not an actual mask, but an ice layer in the snow several inches from your mouth) and once the mask forms then the CO2 builds up in that area and you pass out from the lack of O2 and too much CO2and then well...
This is the concept that the Ava-lung system uses, you breath out through a tube that discharges behind you or at least away from your head thereby greatly delaying the formation of the 'ice mask' and increasing your survival time allowing people to come get you. So if the big orange bag around your head were to slowly deflate it could, in THEORY create some extra space to help avoid the ice mask formation. If someone has more info on this I'd love to hear it