[nimos]

This isn't really surprising. Fiber isn't better because of signal propagation speed, it's all about signal integrity.

https://en.wikipedia.org/wiki/Velocity_factor

[lmpdev]

That and the physical decoupling of information into another medium other than EM

Try running Cat cables on powerlines like Aerial Fibre

[tejtm]

Pedantically, light is still EM.

But I think I understand what you mean.

The shape of individual EM waveforms is no longer relevant instead there are just buckets of got some or not.