I use freezer paper for paper piecing all the time. You have to pull it apart rather that pulling up against the stitching. It is easy to tear, but you need to support the stitching. I like to use it since it is so light weight and I think it tears easy. I also like the way you can iron the pieces down and they stick to the plastic backing. I don't think it will dissolve in the wash since it has a plastic backing.
Sue