I think it would work, you will need to test it first. We got a new mattress and mattress cover. I am going to use the old one for quilt batting. It looks like a thin blanket, no wear as I had it under a mattress topper. Mainly just to store it. I don't usually reuse things but, it is so nice I am going to use it.
It will make for a very warm quilt. Only one like this I have seen. It is washed and dried and ready to use.