I guess I'm playing devil's advocate here b/c I am intolerant to a lot of chemicals, carpets, etc. We are in bed through the night for A LONG time. So if you were intolerant to your bed, bed coverings, carpets, whatever, you would feel great sleeping outside even if you did NOT sleep right on the ground.
My ex husband would sleep outside as often as possible (no, not just to get away from me ;-) ), he said he just felt way better doing that and loved it but he slept on a cot, not right on the ground.
I am really interesting in this and wish I was clever enough and had enough time to make one because spending $250 on a sheet just seems a bit too much for me. I wish they had a money back guarantee and THEN I would try it for sure.