I have found stains come out of 100% and blends well sometimes they don't. I have been gifted with blends onlt a few weeks ago. It was 3 colors totaling about 7 yd. since I don't want them to go to waste I decided after the New Year I will make charity quilts with the blends for the unwed mothers shelter. I am sure some new mom will be thrilled to have a baby wrapped in a cozy new quilt even if it is a blend.
As for grandparents using anything to make a quilt this is so true but remember our grandparents didn't have poly back then it was still all natural fibers. Cotton,wool, linen,silk. Natural fiber breath, poly's don't. You are hotter on hot days and colder on cold days with poly blends. That is why I will also only use cotton batting.