Because, of course, there are still some people who would love to read a book or like to flip the page, so rather than a rectangular screen with scrolling by mouse, hand fatigue.
Because, of course, there are some people who love to read books like pages turning indefinitely. Rather than staring rectangular screen with mouse on hand.
Because, of course, also some people who loves reading books or the like to flip the page to the passive. More glaring screen square with sliding the mouse to stiff hands.