Leather is perhaps the ideal material for a checkbook cover; it gives the cover a soft touch and increases the durability significantly.
Checkbook covers are more than just a vessel for your checks; instead, it needs to make a statement every time you take it out. Although there are other synthetic materials that are also used to make checkbook covers, it is better to stick with leather.
Leather is just better in every way, and if you take care of it, it will stay in good condition for generations.