Interacting with a paper book is a special ritual. Many people enjoy it. But beyond that there is a factor in how the brain works. By flipping through the pages, you activate micro-motor skills. Micro-motor skills in the brain are strongly associated with cognitive functions. Due to this, the use of paper books improves the assimilation of the material. In addition, some principles of speed reading work only with paper books.
Many people buy 5 books at a discount, which lie on a shelf / on a computer. I don’t advise you to do that. This principle may seem counter-intuitive: books are not something worth saving on.
Simple math:
A paper book costs about $25 on Amazon
Kindle version is another $15
Audio version (1 Audible credit) $12 more
Total I spent on the book: $62
By investing money, I make my brain uncomfortable: if I don’t read the book, the money will be wasted. The loss-aversion phenomenon in action.