here is the BPL article on down pants;
i always bring down pants in fall, spring and winter.
i normally only wear them at rest.
it allows me to adapt my sleep system to the temperature. if it's warmer, i sleep in just underwear, if it's colder, i sleep in down down clothing.
it allows me to not need a super warm bag, which has limited use.
when i get up at night and in the morning i am warm and comfy.
for mountain or desert trips, with a big temp drop at night, down pants are lighter than any other warm legwear, even powerstretch tights. so if you want something more than your thin hiking layer for in camp, i bring down pants.
