This thing, despite using "captcha" in its name, is not your typical captcha like hCaptcha or Google's one, because it uses a proof-of-work mechanism instead of writing answers in textboxes/clicking on images/other means of verification requiring user input.

AI bots can't solve proof-of-work challenges because browsers they use for scraping don't support features needed to solve them. This is highlighted by existence of other proof-of-work solutions designed to specifically filter out AI bots, like go-away[1] or Anubis[2].

And yes, they work - once GNOME deployed one of these proof-of-work challenges on their gitlab instance, traffic on it fell by 97%[3].

[1] - https://git.gammaspectra.live/git/go-away

[2] - https://github.com/TecharoHQ/anubis

[3] - https://thelibre.news/foss-infrastructure-is-under-attack-by...: "According to Bart Piotrowski, in around two hours and a half they received 81k total requests, and out of those only 3% passed Anubi's proof of work, hinting at 97% of the traffic being bots."