Actually, I oversimplified. In most cases you don't have to pay $.01 per CAPTCHA. It's usually a fraction of a penny per CAPTCHA. So basically it's good enough

Actually, I oversimplified. In most cases you don't have to pay $.01 per CAPTCHA. It's usually a fraction of a penny per CAPTCHA. So basically it's good enough to protect something that is arguably barely worth protecting. I don't find this compelling. Protecting things that barely need it is already easy using existing techniques.