When browsing anonymously in a private window or with Tor, we often check captchas and other tools. That worsens the private browsing experience and may discourage some people from doing so.
To promote privacy, I think a great feature would be a bot that would pass these tests :). Would it be a problem even with large training data?
Yes, some captchas read your browsing history and website behaviour when I am not a robot checkbox is checked. This is a privacy breach. For this reason alone, this is an essential feature.
Have a brave setting that requires the user to do this once and it is then done forever. The internet then becomes captcha free and my browsing data remains my private business!!