air gapping removes connectivity to the wider world, and a computer system (as in, a system of computers) can totally have value without being connected to anyt

air gapping removes connectivity to the wider world, and a computer system (as in, a system of computers) can totally have value without being connected to anything that is outside of the organization. no need to resort to hyperbolic alien computers that are anyway easily hacked by plucky heroes with a taste for ascii skulls. you're correct in that of course we may want to insert and retrieve data from a secure zone. but when those types of systems are necessary, "manual human intervention" is far too blurry. manual data entry/retrieval by vetted people ? a HUMINT problem the organizations that tend to require those systems are familiar with, and have adequate procedures to deal with. same with printouts and assorted "low tech" issues. inserting a USB key and ensuring that the whole chain doesn't compromise your very valuable system is a far more complex problem that you probably do not want to deal with if you can avoid it. there is a reason the "usb gadget give away" and "lost usb key in the parking lot" are a staple of flashy pentests demos. it works remarkably well, and is remarkably hard to defend against without enacting procedures that make the life very much harder on everyone. (try suggesting epoxying the USB ports of every single computer and servers in a medium to large company to its CISO) like another commenter remarked. it is truly the operational challenges of ensuring your system says properly isolated from the rest of the world that are hard to deal with. cutting a cable is definitely not the end of it. i'm sure people that deal with high assurance environments and are more qualified than i am to answer specifics have their share of stories of creatively compromised isolated environments.