The reason I'm suggesting this, is because if you are a small/medium instance with open registrations, and spammers find and abuse your instance, I imagine that other instances will limit/suspend your instance without hesitation, given how willing some were to limit/suspend the much larger mastodon.social.
But do note this comment on the PR:
“To give some context to people seeing this: this is an emergency feature backport from Glitch SOC to help mitigating an ongoing spam wave, this feature may not make it in a next release, or with significative changes.”
Edited to add: multiple people have rightly commented on the accessibility concerns with hCaptcha: hCaptcha is really really really bad for blind and visually impaired people.
Please have a look at this excellent reply for more details:
