I had been learning my target language mostly from books (and then watching/listening to media for osmosis) for years before I discovered Pimsleur. I can confidently say that Pimsleur increased my skills by orders of magnitude. Being forced to 1) speak out loud, 2) create sentences under time pressure and 3) absorb language rules implicitly rather than explicitly was a major game changer.
My only disappointment is that Pimsleur only created 2 levels for my target language, so after I had repeated them a number of times I had to look elsewhere for other (less effective) materials. Recently, I've been using the ChatGPT Voice Assistant to try and approximate the Pimsleur experience - it works to some degree, and it's novel that I can ask it questions during learning, but it can't really offer a curriculum in the same way.
My only disappointment is that Pimsleur only created 2 levels for my target language, so after I had repeated them a number of times I had to look elsewhere for other (less effective) materials. Recently, I've been using the ChatGPT Voice Assistant to try and approximate the Pimsleur experience - it works to some degree, and it's novel that I can ask it questions during learning, but it can't really offer a curriculum in the same way.