I recently learned Swift & Metal this way - knowing Python and other languages, I kept pasting my pseudo-code, asking GPT to convert it into Metal/Swift, and then iterating on that. Took me a week or two to get the language without reaching for any sort of manual/tutorial. Speaking from experience - it would take me 2-4x as much time to learn the same thing otherwise.
If GPT was any better, I'd have no need to fix the code, and I wouldn't learn as much.