Sleeping bags are available in a wide variety of ratings. There are non-electric liners available that can be inserted on cold nights. For far less money than they are asking, any a bag can be improved.
Relying on battery power for this, sets up a dangerous situation. If people find themselves trapped out in the wilderness for much longer than expected, with a good quality traditional sleeping bag, it continues to work. If they are caught out with a battery-powered bag, it will stop working once the battery dies. Now they are using a bag which is meant for more mild conditions. I have tried gloves and
boot liners with similar gimmicky electrical
heaters. Once the power runs out , you freeze. I can't see this thing working as well as a product relying on insulation.
Think of what we would do in a household situation. A choice is given to spend money on good quality insulation or to spend the same amount of money on baseboard heaters. The only sensible choice is to insulate. Our bodies provide heat for free. When using a proper sleeping bag it is possible to get a good sleep in extreme conditions. Mountaineers do it all the time. I have spent many snowy nights sleeping in unheated vans and other vehicles at my job sites. If I had relied on something that required power or something that could fail electrically, I wouldn't be writing this , because I would be frozen somewhere.
It would be interesting to see if there are any Mountaineers or serious adventurers using this product. For me, that would be very surprising. It seems like something that might be useful for car camping. Even then , for the money spent, a very decent quality bag could be purchased.
This is one of the worst ideas I have seen presented on permies, due to the extremely dangerous situation that it sets up for the novice camper. I'll bet that somewhere in the fine print, when you buy this thing, there will be a warning to always be sure and have
enough warm clothing and blankets to keep you alive out there.
It's always a good idea to have some sort of backup. When I was quite young, I may have thought that this was a great idea. We won't find any 70 year old wilderness campers frozen in these things, after an unexpected blizzard prolongs a camping trip by several days. It seems more like something that young snowmobilers or novice ski campers might be foolish enough to try.