Great booties so far
I just used it once. It wasn't snowing, but it was pretty cold and they kept my feet warm.

Men's Down Booties are very light and compress small
These booties are indeed quite packable, and you can easily find a tiny space in a backpack to take these along for a cold climate when the hiking boots--and your feet need a break. I have size 11 feet, and I thankfully chose the XL size. One issue, which is to be expected, is that there's not much insulation for the bottom of your feet against a cold ground, so I added some foam insoles purchased in a local store. This would give an extra 1/4" insulation at a fraction of an ounce additional. The weight (without the sack) including my foam inserts comes to 8.5 oz per pair.

Very good
Worn at Mt Rainier during winter camping conditions. Still was a little cool but I get cold easily. Easy to pack. Agree that they are not for exploring very far outside the tent. Would not go winter camping without something similar.

Warm and light
Took them on a backpacking trip. They pack easily and are lightweight. Put them on to sleep inside my bag, and feet were toasty all night. Bottoms look lke they could take a quick bathroom break outside the tent, but not much more. Not well soled.

Light weight, but bottoms should be waterproof and insulated
I just returned from 5 day winter camping trip in northern Maine. Before I left, I tested the booties and the bottom of my feet became cold quickly. I used contact cement to afix 1/4" neoprene which is waterproof. They worked wonderfully but would have been a disaster as purchased.