A rounded and backed case binding gives your spine a classic rounded shape. This older style of bookbinding was used to accommodate hand-sewn signatures and build a shoulder and hinge for the boards of the cover. Modern rounded spines are more of an aesthetic choice that can give your book a classical old-world look and feel. As seen in the photo, a rounded and backed case binding will give your project a vintage aesthetic. You can even pair it with a raised band spine to really lean into your book looking older.