Probably due to "PoW" being power-hungry, but that's largely false because you only apply PoW here on users that are abusing the system.

Allowing abusers to freely abuse would cost even more power than just forcing them to do the work.

The project is very new, I haven't started promoting yet. The Codeberg development was purely from word of mouth :)

disclosure: I'm the author of mCaptcha

mCaptcha is in the process of being adopted in Gitea and Codeberg. See recent Fediverse post from the project account: https://gts.batsense.net/@mcaptcha/statuses/01G9KRBRC8CRC9M3...