Wouldn't this be considered the same attack? Users would connect the cable, unlock their phone, and then would need to explicitly "Trust" the external device attempting to connect to their phone via USB.

I suppose the difference is that people may be using the cable to connect to a device where that prompt is expected, in contrast to the "charging port in an airport" scenario where it would seem appropriately alarming.

If the phone is unlocked, a badUSB-type device can do anything a keyboard can do, so it’s far from completely harmless.