I won't argue that the benefits are at the user's cost since I pretty much always have to request a new set of images as the ones I get tend to be so distorted

I won't argue that the benefits are at the user's cost since I pretty much always have to request a new set of images as the ones I get tend to be so distorted I can't make out a letter. But how is this (cracking audio CAPTCHA) an example of how image CAPTCHA is a weak spam deterrent? I don't see the connection.