[Nextgrid]

> That is an extremely fragile solution.

> By default ethernet is very open. It is very easy to bridge it with other devices or routers to announce themselves and start routing. It happens all the time on what are supposed to be closed networks, I've seen it.

The reason for using Ethernet and browsers is that both are built into pretty much every computer, don't require any drivers, admin privileges or persistent software.

The idea is to replace USB, serial or some other point-to-point link which would require platform-specific drivers and client software. Most peripheral connections for printers, etc don't employ encryption on the control cables and the world hasn't ended, so physical security here is good enough in practice for the majority of purposes.