Electronic dictionary or paper dictionary

Teachers always suggest us not to use electronic dictionaries. I once tried to use a paper dictionary but it cost me a few more time than searching on electronic dictionary. Although I could get further information such as different meanings, examples, synonyms, and antonyms while using paper dictionary, I save a lot of time by using electronic dictionary. I could just turn on the power and entered the word I wanted to search, and then the meanings will be showed on the screen. It helped me a lot when I had a large amount of articles to read. I will use paper dictionaries as possible as I can because I am English major.