One of the fundamental security issues with USB is that any device can be anything; pretty much any device can hide a keyboard or other HID node to covertly take control of a computer it’s attached to. OSes these days take the brute force approach of throwing up a dialog every time you attach a device, but that’s annoying and we all just click through those dialogs anyway.
But what if the connector itself had to have some visible-to-the-naked-eye encoding, like color bands or a QR code, declaring what kind of device it’s allowed to be? Connectors could then have photo sensors that scan the marking and only allow USB nodes to attach corresponding to the marking. So you could look at a connector with your own human eyes and know what it's allowed to be. Then just put a little fiber optic line in the cable so the connector on the computer end can validate the codes and allow-list which devices are allowed to actually attach
