I would definitely use for backings....and lucky you to find it at a great price!

I would use it for backings ! If you can get it at a great price.. go for it. The poly in it will wear better than cotton. One note .. some blends do have more pilling than some cottons. That being said .. I just purchased a very expensive set of sheets 100 percent cotton high thread count etc. .. and guess what they pilled at the wash...so you just never know.

The poly cottons will outlast the cottons and not fade as much. I used a mixed fiber bed sheet for a comforter I made us and it seems to slip easily off the bed. I used my usual poly batting. With the heat my Husband puts off, it is way too warm to use.
I have some poly/cotton fabrics I would like to use but, I am trying to use my cotton fabrics first.