No idea about the wiggy stuff never heard of it, but I often used my old style hollow-fill bags to dry stuff as I slept, including myself and everything I was stood in, generally the stuff/clothes would dry well. Never had a soaked bag that I
HAD to sleep in whilst I too was soaked, but if there were no other option I'd have had too. I have slept in a wet bag on more than one occasion, and thats better IMO than being wet ones self and having to get into a dry bag.
Can't say the prospect of a wet self and wet bag would be that appealing but in temperatures that allow things to remain wet, rather than frozen, and provided the human heat source had enough fuel to keep generating body heat, plus enough shelter to keep off further wetness, slow further heat loss and allow things to warm, whilst a nasty prospect I'd say getting in the wet bag with wet clothes, all after a good ringing out of course, I'd have to say it's more than survivable.
The ability to self dry ones self/ones bag like this is a major consideration, in my experience, in choosing the type of bag to take on any given trip, if there's a chance of getting wet, synthetic, if it's dry (continually subzero), then grey goose down is the boy.
So, this Wiggy's claim maybe a marketing gimmick for them, but it's actually a well known property of quality synthetic bags.
Get your bag wet you deserve to die? Thats harsh Mr Thrills
Back on topic
Other than a little cotton mixed into a synthetic material to use as trousers (or fine cotton outer layers, ventile type stuff), I'd avoid cotton for outdoor use, in any mix, like the plague, especially next to the skin.
That said it all depends what one is up to with ones clothes as to what the best clothing/materials for any given activity is.
On here we seem to have a mix of outdoors type people indulging in a wide variety of related but very different outdoor pursuits, with correspondingly different levels of anticipated risk and degrees of personal commitment.
It's not that committing to nip off to the woods for a night or two, a few miles from the car, with full reception bars on the mobile. Where as hand hauling all your kit across the greenland ice shelf unsupported, is rather more committing.
The kit for the trip to the woods doesn't need to be that specific, where as a trip to somewhere remote and cold, or hot, needs to be well thought out and tested.
The weather is only one consideration for clothing choice, other environmental factors/considerations need to be made and a balance sought.
I favour synthetic base layers, polly cotton trousers, and a 100% wool mid layer. Shell choice for me is generally gortex for mountaineering, ventile for general use and PVC oilskins for the incessant west coast deluge.
I've come full circle with clothing and now I've come to the conclusion that the 100% wool mid layer is a good compromise between insulation and additional environmental protection for the sort of stuff I do. Of course I'd choose a different mid layer for pulling a sledge across the greenland ice shelf, but I'm not planning it any time soon
If one can go the wooly underpants though, then the lifa marino synthetic mix by HH would be my choice, but I can't go it myself. I'd never use a wool cotton mix next to my skin if there was a chance of getting wet with no chance of a change or reprieve. But I'm sure it would be fine for an evening or two out in the woods.
Provided your life doesn't depend on it, I say; try it out and see how you get on and adjust accordingly until you find what works for you for your given pursuit.
