My now deceased aunt used every scrap of anything. She made dozens of poly/knit quilts and just used a cotton sheet as backing. As someone else said, the seams do come out fairly easily. I inherited the entire stack of quilts, many of which I gave to my kids, but the ones I kept get plenty of use covering all our unholstered furniture where the cats and dog make their nests. Very easy to wash and dry also.
She did make some puff blocks......put a tiny pleat in each of the 4 sides of a block, then sewed them together.