No. It does give you a good idea that someone is human. A robot can send captcha to be solved by a human. Captchas are cheap to solve. $2/1000 recaptcha
DeathByCaptcha do $1.39 (or $0.99 under some circumstances) per 1000 solved captcha and they accept Bitcoin.
We provide two different types of New Recaptcha API:
Coordinates API: Provided a screenshot, the API returns a group of coordinates to click.
Image Group API: Provided a group of (base64-encoded) images, the API returns the indexes of the images to click.
I disagree. They make you render the captcha instead of just paying for the response key to put in the form. Each recaptcha can have multiple required solves.