Captcha Data has been used to traon ML models for a very long time. What's changed recently is that simple stuff like OCR has already been solved and democratized so the simple puzzles no longer work.
I'm not talking about the simple puzzles or 'words' that reCaptcha initially used to show. I'm talking about their 'improved' way of testing whether you are a bot by just making you click a checkbox. That doesn't work anymore (most of the times).
