In an ideal world maybe learners could focus exclusively on listening and speaking first, then move on to kanji later. But writing is a very useful tool in learning, and having access to that tool can help speed things up.
Like most things in life, a balanced approach is probably the right one. But you have to know what your goal is. Our brains are lazy, they only get better at what we make them get better at. If your goal is to just read kanji, practice reading kanji. If your goal is to understand and speak the language, practice listening to and speaking the language. But if you want to have a balanced language ability, you'll need to practice it all.