Using a laptop or e-reader to read textbooks is awesome for a couple of reasons. First off, having multiple textbooks doesn't weigh anything, and I can carry them around at all times. Secondly, when doing assignments and the like, I can bookmark the answer section in the back, and flip back and forth between questions and answers arguably faster than I could with a paper book. Finally, the best part of electronic books is the ability to search through it. Every definition in the book is a Ctrl+F away.
So maybe reading books electronically isn't as great when you're doing a lot of actual reading, but in my experience using more math/science textbooks, electronic wins out every time.