@Tobias - exactly. I don"t understand what's the long-term trouble with integrating captchas already integrated into Joomla here with SPPB. Posting suggestions like "use geoip blocking instead" is completely unacceptable.
Please integrate it once and properly so that it does not break every couple of weeks and is usable with whatever Joomla recognizes as captcha. :-(
Now I'm again stuck with the hCaptcha things that users don't understand, or the bad joke integrated into the SPPB form addons with preconfigured static Q/A, which is completely ineffective against spam.