Looking for feedback from hikers who use sleeping bag liners. I'll be sleeping in long underwear and using an EE quilt during colder weather so I'm not really worried about keeping a bag clean. I would expect some extra warmth on the cold nights. I would expect that I could use it alone for warmer weather instead of the quilt. What are your thoughts? Worth the weight? Luxury item? I've read about negative experiences of it feeling confining. Just curious about your experiences and thoughts.