That is exactly what it is.

EDIT: From Google's own reCAPTCHA website - https://www.google.com/recaptcha/intro/v3.html#the-recaptcha...

> Hundreds of millions of CAPTCHAs are solved by people every day. reCAPTCHA makes positive use of this human effort by channeling the time spent solving CAPTCHAs into annotating images and building machine learning datasets. This in turn helps improve maps and solve hard AI problems.