That's different. iOS has the same "Trust this computer?" prompt before it attempts to pair. But in both cases the phone still has a data connection, which leaves it vulnerable to any kind of security compromise (such as GreyKey), plus if the computer has a "lockdown record" it gets to skip that "Trust this computer?" prompt anyway (a lockdown record is a thing a computer gets after pairing with the phone that lets the computer prove it's already trusted to talk to the device).

But what this article is talking about is after 7 days of not being unlocked, iOS 11.4 won't even enable the data channel on USB, which means computers with lockdown records still can't talk to it, and presumably devices like GreyKey can't compromise the device.