Pillowcase and Pillow Sham The Pillowcase and the Pillow Sham might sound similar and look similar but they serve different purposes. Pillowcases are more functional while pillow shams are less functional but more decorative. Summary The Pillowcase and the Pillow Sham might sound similar and look similar but they serve different purposes. A pillowcase (pillow slip) is used to cover the pillow that is used for sleeping and is usually open at one end with no type of closure. Pillow shams are typically made of fancier material and designed to match or compliment your Duvet Cover (Doona), Comforter, Quilt or…