Written language or conversational?

Everybody has different aims to consider when learning languages. One of them is whether to focus on written or conversational language. Of course, you don’t have to focus entirely on one (and I wouldn’t recommend you to), but it will affect things like the type of texts or materials you study from.

At the moment, I’m studying a reading textbook, which has short essays followed by comprehension questions. My teacher is careful to point out which things are only suitable for written texts (and so I should avoid saying things that way). There are also discussion questions so I can get my fill of speaking practice. This method suits me right now as I am using language mainly for work, where I am communicating a lot by email.

My friend is using a textbook that is made up of conversations about various topics. It includes follow up questions and audio as well. This method is great for beginners and people who need language for everyday situations.

Which method do you prefer? Do you think a distinction needs to be made?