Digital text books are used to enhance learning and minimize the burden on students shoulders. Digital text books are usually online and you need a single laptop and internet connection if not downloadable else you can store in a computer and then can be used by the students. But this is not the replacement of ordinary printed textbooks. On primary level its not easy to use as the students are very small in age specially mental age. Assessment may be done online, verbal and or with written test.
Digital textbooks are meant to replace traditional textbooks. However, infrastructure issues have been hampering this initiatives since the beginning. Downloadable versions are plagued with copyrights infringement and as such, they cannot serve their original purposes.
A great potential of digitisation is to dynamically adapt the content for individual learners, as they make progress with individual units. It is also fruitful for teachers who can customise textbooks each year to ensure the content is relevant and includes local references (as well as global ones). I believe Pearson offers these services and there are surely other publishers.
Shamsul Rizal Mohd Rosedi Yes, I agree with your opinion that infrastructure issues can be a very difficult problem to handle. Digital textbooks can not save money in the long run. It also arises some challenges.