I don't think it's to avoid a security issue. Almost any Mac made in the last 5+ years has had sufficient security to stand up to nearly nation-state attacks on

I don't think it's to avoid a security issue. Almost any Mac made in the last 5+ years has had sufficient security to stand up to nearly nation-state attacks on its disk contents. What I think is far more likely: it's a dark pattern to discourage people from doing their own backups. One of selling points of iCloud is scaring people into the possibility of their stuff being lost from their phone getting destroyed/lost/stolen. Up until this change was implemented, it was painless and transparent to do backups of your phone. You just needed to have your Mac or Windows computer turned on and your phone on WiFi with power. It Just Happens. This is also a convenient way for law enforcement to get people's iMessage history, because iMessage backs up by default to iCloud, unencrypted, including the user's iCloud encryption keys. Without this, if LEOs wanted a criminal's messages they'd have to pound sand. We know that the FBI has at least a somewhat sympathetic ear at Apple, probably because keeping the FBI happy means Congress doesn't start applying levers on the company. Given the timing which is right after they deployed the enhanced iCloud security that supposedly E2EE's everything in a (again, supposedly) very secure way, I suspect this was a tradeoff they made to keep the FBI/Congress happy, while also boosting revenue. 'Hey, we'll nerf the local backups, and don't worry too much about enhanced security, most people won't turn it on because it's a pain and we'll put scary warnings on it.'