Many people still use printed versions of diaries. When a person writes by hand, the brain in the process of writing processes the information transferred to paper and it is deposited in memory. On this topic, you can read the research of Professor Audrey van der Meer from the Norwegian University of Science and Technology (NTNU).
There are thousands of different free templates and daily calendar grids in the world for every taste. There are strict and classic ones, there are multi-colored ones with photographs, there are dated ones, and there are no dates.
There are even whole communities of people obsessed with planning. Each of them is trying to create the best scheduler for their tasks and goals.