> For me, all captchas are a stain on the web - in most cases, shifting (and multiplying) the wasted human hours from the company collecting data (eg the owner of the contact form) to the user (the person completing the contact form).

I run a contact form for a small business. Explaining to them why their tiny website has tens of thousands of spammy requests filled with porn keywords is not easy. Of course webmasters add reCAPTCHA, because they're vastly outnumbered by bots and users.