SPDIF cable same as coaxial cable?

It’s worth mentioning that a “composite video” cable is also the same as a digital coaxial cable...same 75 ohm characteristic impedance, same bandwidth. A good AQ YIQ or Monster Silver Digital from yesteryear serves nicely...

Also, one reason often given for preferring coax over optical is that the addition of an LED and photoelectric receiver to the signal path cannot, in most cases, help, when the signal originated as and must return to electronic impulses. 

I believe it’s moot. Digital data is just that. Until it’s processed by a dac, it’s just ones and zeros. Without form, without sound, going where no man has gone before. 

crusty and yeti have it right

clwinbe hasn’t a clue

here is a tutorial to help educate
https://darko.audio/2018/11/why-isnt-digital-audio-just-ones-and-zeroes/

The digital coax I see is 110 ohm.
That being the difference.