I always thought that was a suspect recommendation. In wet cold environments, they don't work.
Mike Clelland uses thin neoprene socks to keep his feet warm in wet conditions up in Alaska. His recommendations are usually pretty good. They've worked for me. But I've never used them in snow, then, either.
One thing I've always wondered about that no one ever seems to talk about is the R-value of materials for insulated gear other than sleeping mats and fill. For instance, if you have two down jackets that have the same down fill, but two different shell materials, one which has poor R-value (conducts heat and feels cold to the touch), the other with a shell that has great R-value (feels warm to the touch), the second jacket will feel warmer. This is part of how R-value in houses is determined... a stone floored room will feel much colder than a wooden floored room, though the temperature of the air is the same, unless the stone itself is heated.
I'm wondering if neoprene, because it quickly feels cold to the touch, will, at certain lower temperatures and contact with snow, will feel much colder than gore-tex socks, even though the gore-tex is thinner...