I think the idea is that if you want to transmit quantum information you need a quantum internet.
There are many cases where you would want to transmit quantum information besides using it as an encryption scheme. For example, if a scientist wants to run a quantum simulation in the cloud, and then they want the quantum state to be communicated back to their local quantum machine _without_ collapsing the wave function, then you would need some kind of quantum link to do so. If you want to send it through the classical internet you would have to collapse the wave function and send classical information.
There are many cases where you would want to transmit quantum information besides using it as an encryption scheme. For example, if a scientist wants to run a quantum simulation in the cloud, and then they want the quantum state to be communicated back to their local quantum machine _without_ collapsing the wave function, then you would need some kind of quantum link to do so. If you want to send it through the classical internet you would have to collapse the wave function and send classical information.