Leather will perforate, but a bigger issue may be that it sticks to the bottom of the foot. A leather foot for straight stitching has rollers on it so the leather doesn't get bunched under the foot. Because a hopping foot doesn't come in contact with the fabric that much, it may be OK. Also, the finish on some leathers makes it easier to sew. A trick to sewing leather is to put a piece of tissue paper over it and sew thru that so the foot glides over it. You could draw the quilting pattern on the tissue and use painters tape to position it. As suggested by other posters, try on a scrap.