I would think you could use most anything to provide some cushion. Only word of advice is at the end of the day, pull it out and hang it up somewhere. If not, it's going to be a place for mildew to grow.
If these are the same thing as the ones I got at Sears (they probably are) then I would recommend them. We've used them under and around our small pool on our patio for the last 3 years and they seem to be holding up great and haven't even gotten too bleached out in the sun.