This course forces you to speak and think in Italian every day. That’s as close as it gets to practicing conversation or taking a lesson with a native speaker. For that reason, if you were to pick only one self-study resource, you should go for this one.
On the other hand, you certainly need to develop by other methods a variety of skills that are not covered here (especially writing and reading). However, there’s no learning resource that alone can lead you to fluency, but you could say that about any course.