I can't agree with this when it comes to language learning specifically. I've used all sorts of tools to learn the language of my in-law side of the family: books, audio lessons, videos, tutoring, apps, etc. I've never made as much progress as I have with Anki. My language skills have improved in leaps and bounds so much with Anki that I now rarely bother with anything else, other than for sentence mining to create more Anki cards (e.g. from grammar books or apps) or just for a bit of variety to make the process more enjoyable. I actually find classes/tutoring (traditionally seen as the "best" method) frustrating because of how slowly I learn with them compared to Anki. In a 1 hour lesson we might cover a handful of concepts and words/phrases that I will almost certainly have forgotten most of by the time the next lesson comes around. In that same hour I can create and review a ton of Anki cards and I'll remember most of them.

With tools like Google and Microsoft's neural TTS and Anki's AwesomeTTS add-on my cards have audio that is so realistic that I am also constantly exposed to near-native listening. I do 3-way cards (Writing only -> English, Audio only -> English, and English -> Other language) so I'm actually getting a reasonable simulation of real life practice (reading, listening, speaking) on an individual sentence basis. My process is: (1) find a high quality sentence from a book / app / website / ChatGPT (with verification from a native speaker); preferably one that is fairly simple apart from a single word or verb conjugation that I haven't learned yet, in keeping with the i+1 rule, (2) create an Anki card for that sentence using my own custom note templates, (3) add audio with AwesomeTTS. Creating a card like this takes me perhaps 10-20 seconds as its mostly just copy-pasting and clicking a few buttons.

Of course to become truly fluent you need practice. But when I practice I'm already able to follow the gist of conversations and I can stumble my way through speaking in most situations: I've got a huge head start thanks to all the latent vocabulary and grammar that my brain knows thanks to Anki, instead of having to constantly look blankly at the other person while I pull out Google Translate.