I love being able to slip on something quick on my feet if nature calls during in the night. And having something warm and dry to put on my feet when my runners are wet is so nice. But I, like you enjoy hiking more with a light pack. I have been intrigued by the durability of the polypropylene bubble mailing envelopes I have received from some online sellers (like Amazon), and quickly made up some light weight 'camp slippers' from one for a recent trip. These were just made with packing tape very quickly allowing me to get a snug fit custom to my feet. I'm considering these a prototype (ugly!) and will make them better if I end up liking using them.
Pro's: These weigh 1.15 oz for the pair, are warm and don't absorb moisture, provide descent padding and protect my socked feet from dewy grass.
Con's: Not breathable in the toe area. But dry wool socks seem to make up for this. I have thought I may try perforating the tops of the toe area to allow them to breath a bit more.
My 2 cent idea... worth the price charged 🙂