A very interesting concept---wonder why no one has thought of it before!
You are right about "depending on the temperatures"; the spec in the link says "Specifications: Temperature rating: 45 degrees Fahrenheit."
The way things have been this past winter in my area, that would have been plenty. Minnesota, I don't know.
A better insulated same style suit doesn't seem beyond present technology.
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"Better is the enemy of good enough."