: Been a while since I've seen posts about the sponson guy's rantings.

So you know the author of that thing? i never seen that site before.

Theres no real advantage in arguing the pros and cons of whichever new (or old and rediscovered) thing that shows up, ive heard a lot even just about simple paddle floats and seasocks.
Usually that kind of devices spins out from one particular situation where it could have been useful, and often its very specific, even the "one shot deal" things could have been very welcome in certain accidents, theres so many events happening that you could find a fitting one for every "invention" that crosses your mind.
Ultimately everything has their weight in the decision we take, that could be relying on skills or the "technology" we have, and both can be greatly overestimated, its human nature to make mistakes.
I wouldnt use those bags for everyday paddling in the same way i havent used a sprayskirt in the 3feet deep pond behind my house, but if i was going to do some extreme island hopping id look into the possibility (adapted to my own liking, the way that site presents them its not what id want).

: If you end up regularly using them after a
: thorough trial period I'd be pretty amazed.

Im pretty sure that if anyone would end using any emergency device regularly lots of people would be amazed... that that person would keep being in that situation that is.