"Such systems make it impossible to intercept
and read messages sent over a network, because
the very act of measuring a quantum object
changes it, leaving behind telltale signs of
the spying.
'It’s unlikely everyone would need this type of
technology...'"
On the other hand, you don't need a classical switch in your house to get on the Internet. If quantum repeater networks ever roll out to people's homes (a very long time from now), the switch will only need to be within a hundred kilometers or so of the user. By then, this sort of construction won't be out of the question for telco substations. Still, an entirely solid state solution would obviously be preferred.
So, in that sense they really are "classic" switches in terms of representing the raw fundamentals of functionality for the purposes of experimentation, but not in the sense of "classical physics" where the off state is caused by introducing a physical air gap to the circuit.
In theory, it's actually impossible to secretly snoop on such a connection, not merely "very hard".