We have access to an unlimited supply, we have used one for that purpose, it was not great but okay, as in anything is better than nothing...You could pick up something from the Salvation Army that would be cheaper and lighter.
We consider the moving pads to be a one use item. They do repel some moisture, they do fall apart if you try to wash them. My dog sleeps on one when we are car camping, I cover the seats on picknick benches with them. They weigh a ton when wet. I put one under my hammock, so if I fall I have a little padding. I also cover the back seat of my vehicle with them, so I can throw out the whole blanket when the trip is over.