Paper dectionary v.s. Electric dictionary

I read today's Asahi Shimbun and found one interesting article from it. These days the electiric dictionary(in Japanese Dehshi-jisho) has become popular. Especially among us students, such dictionary is useful to look for the word fastly and easily. On the other hand, dictionaries which made from paper has reduced its user. The sales decreased by 40% from 1998. So the makers are surprised at this state and seek the new way to approach their business to electiric one. From this article, I remembered that some my teachers said we should use paper dictionary. I was convinced that my teacher was right, without thinking why they said so. Do you know why paper dictionary is good for us to study? Also, I have paper dictionary but actually I don't use it because I rely on my electric dictionary. But I notice that we should use it... How can I use it in which situation...?