IMO I think the OP’s question is pretty good. I would also like to know other people’s opinion about the security concerns of CAPTCHA bypass with previous security concerns, especially given the plethora of recent OS patches with the last one being specifically about failures in WebKit privilege access.
the link from Apple that the OP had provided really only gives a description of the feature and no other information on the potential benefits (besides convenience).
theoretically if you don’t have a bunch of windows open on your phone and there’s no remote access capability to your phone or any accessibility features, iCloud, handoff, or other settings set up automatic CAPTCHA bypass just makes life less annoying, but personally I’m a little concerned after having our network compromised a while back and still dealing with some unexpected behaviors which continue to be resolved through Apple’s security updates.
thanks