Yes, speaking is the best way if your main goal is speaking.
But for some people skill of beautiful and expressive writing is more important than fluent speaking. I concentrate on writing more than on speaking, because I can use more vocabulary and write on topics that hardly being discussed in standard basic conversations.
In my opinion, speaking is more about your self-confidence rather than about your knowledge of the language itself. It probably sounds strange, but this statement even doesn't need a proof. Just look how many people know grammar and have very nice vocabulary, but still have problems with speaking even on simple topics. I can expess my idea aphoristically:
"If you want to learn a language, you should write. If you want to speak, you should just speak."