Skidoo suits?

Yes they could be using thinsulate fiber in them for the quilting.

Remember that they are designed to keep you warm in a blizzard riding a machine that can go at speeds of 70 mph or more.
counting windchill it means an equivalent temperature of -60 degrees Fahrenheit or lower some of the time.
They are usually too warm to work in at 0 degrees Fahrenheit.
My last skidoo suit was lined with a fairly coarse fleece pile instead. It was able to keep me warm at -40 with no trouble and if I had to work hard in it at that temperature there was a good chance I would unzip the collar and maybe some of the leg zippers just to avoid sweating up.


Could you just lay down in a snowbank and go to sleep in one?
Yes.
You might want to protect your face, hands and feet a bit better but if you have the complete suit with the mitts and felt lined boots, the helmet and face mask, you are not likely to freeze anything. You might have to get up and move around a bit to warm up a few times if it is really cold.

Or maybe just light a big bonfire and stay up telling your buddies lies about how much better your love life is than theirs.

What Paul said about sleeping out if you had to is pretty much true.