as modern citizens, movies are part of our lives, our experiences of the world around us. watching movies is a great way to passively absorb english, especially english idiom. it is important to watch movies where the dialog is well-written and non-dialectic or you will pick up bad habits. dramas are usually those with the most attention paid to the quality of writing. while english has changed significantly in the past century, the variation is less significant in spoken english so older movies with good dialog are far more helpful than older books.
television often has less quality writing when compared to movies but there are certainly many exceptions. this is certainly a passive learning experience but if you have finished your daily language exercises and want to relax by watching a series, it will help you get a little extra english in your day. the big benefit of television over movies is that you can build a language relationship with characters over a long period of time, not just a few hours but often dozens or hundreds, if the show lasted many seasons. that allows your ears and brain to get used to the patterns and voices you will experience and gives you a chance to focus more closely on the words themselves without being surprised by the way they are spoken or a new idiomatic style.