Right, the 1.8C difference is substantial in terms of human physiology and indicates a diminished level of comfort as the body fights to keep the temperature up.

I also found it funny how they mentioned that modern clothing keeps you warmer longer once you stop moving, then tried to minimize the significance of that. There's a reason "cotton kills" is a cliche. Modern fabrics, windbreaker shells, and engineered layers don't make a huge difference in warm, dry, active conditions - it's when things go sideways that they can be the difference between comfort and fatal hypothermia.

There are times when layering is not the way to go. One of them is heavy activity in extreme cold. Layers can cause moisture to freeze in bad places. Having lived in a place that often got down to -40, I was always most comfortable with a light synthetic shirt under a single winter coat. No complex layers. And waterproofing isn't needed as there isn't any water around.