Rokwiia
WKR
Dry feet are warm feet, if your feet sweat they will freeze, period.
That's only partially correct. Your feet can be wet as long as warmth is generated and the wetness is contained. That concept is central with a vapor-barrier system.
As your feet sweat, they will wet your boots. At some point, usually when you stop walking, your boots will freeze. A vapor barrier contains the moisture and prevents the boots from getting wet and thus from freezing. Just try wrapping your feet (including socks) in two grocery-store plastic bags and putting them in your boots. as you hike, your feet will become drenched but the moisture will stay within the vapor barrier and not effect the integrity of the boots. The boots will stay dry as a bone. Once you stop walking, you remove you feet, dry them, put on new socks and grocery-store bags and you're good to go.
That concept is what makes white and black bunny boots work. You can wet out the boots without issue as long as you are moving and generating heat. Once you stop, you remove your socks, dry your feet and the interior of the bunny boots, put on new socks and you're as good as new. In this particular case, the insulation in the bunny boots is contained within the rubber boots so the insulation can never get wet.
The vapor-barrier system can be expensive, specially-designed socks or they can be grocery-store bags.
Boots that have a removable liner also work well if you bring an extra liner(s). Remove the wet liner and replace it with the dry liner.