Have you bored to carry the heavy book for study or work all the time? if you say yes , E-book is the better choice for you. why? beacause It is lightweight more than textbooks for example ipad weighs only 0.469 kg. while text-book weighs around 1-2 kg. per book.
Moreover people can carry many text books in 1 tablet because it is in the digital data form. It mean if you have to carry 3 book to study you can get it in weight only snacks reputation 5kg. Instead 12 kg.