It cradles my butt
I love this seat in my pack. There are so many things I have ended up using it for, extra spare pillow, seat on rocky terrain, shelf to set things on to keep them off ground, insulating seat on snow.
Best uses are probably protecting your butt from really rocky terrain or really cold terrain (sitting on snow).
Self inflating so no fuss there. Sometimes I actually pack it inflated to use it as a blocker in my pack to aid in sorting. I always take it with me.