Not only that but by taking classes you're exposed to related areas that self-learners would never cover on their own. In my case, the professor who taught one of my classes also taught and did research in linguistics. I learned a ton of stuff about the morphology and syntax of the language I was studying through office hours and an independent study with them. In terms of just learning the language to get by, my time could have been better spent cramming anki or something, but ultimately I feel like I have a much deeper understanding of the language because of this.

I do agree with double majoring in something useful though. Even though I enjoyed what I studied, if I hadn't majored in computer science as well, I don't know what I would be doing right now in terms of employment.