While hard copy books might be on their way out with the increasing popularity of e-Readers and digital reading, most people are still stuck in the olden days of just plain reading a book. The great thing about the Kindle and other e-Readers is that the devices always save your spot, even if you have to drop the reader in a mad dash.
With hard copy books, its common to lose your page even by simply dropping your book by accident. Say you get too tired and the book flops right on your face. I know it’s happened to me. The Reading Ring slides right onto your thumb and holds your spot open no matter what might arise, except maybe if a giant boulder fell on you cartoon style. Then you’d probably have to go back a few pages.