EOF uses fiber optic connections to transmit data. Fiber-optic connections rely on glass housed in a protective sheathing of strong flexible fiber to guide pulses of light which carry the data from one end of the strands of fiber to another. While copper degrades over distance, this does not happen with fiber. EOF connections are also more secure because cutting into a fiber network is more costly than tapping into a copper network.
The main advantage of EOF is that you have the ability to transmit large quantities of data very quickly and with distance because glass transmits signals far more efficiently than metal.