The blog post notes that the Safari that is driven by the automation cannot interact with other windows or user preferences. It also requires that the user has had the "enable remote automation" enablex, which is only possible if you have enabled the developer menu bar.

In addition, automation windows are shown with a different coloured bar and have a "pane" over the window so that it won't receive stray mouse or keyboard input.

> particularly given how Apple has been losing their quality edge of late

I know this is a subjective opinion and I'm not going to touch upon whether I think it's true or not, but I want to know why you even said this bit? The common claims about Apple's quality slipping don't have anything to do with security. If anything, Apple's security is getting better and better over time.

It is very noticeable that their software quality is dropping. It is parsimonious to assume this will impact complicated API surfaces negatively.