I would have thought that something so light keeping you very warm would be something useful to have on a ride, as @gillies said if you've stopped for a mechanical, cafe stop, or it gets cold suddenly - from the description its purpose is more as an emergency extra layer that barely adds bulk or weight to your pockets, rather than something you wear from start to finish of the ride. And walking around a warm house isn't exactly the best test of a piece of cycling clothing?
I would have thought that something so light keeping you very warm would be something useful to have on a ride, as @gillies said if you've stopped for a mechanical, cafe stop, or it gets cold suddenly - from the description its purpose is more as an emergency extra layer that barely adds bulk or weight to your pockets, rather than something you wear from start to finish of the ride. And walking around a warm house isn't exactly the best test of a piece of cycling clothing?