Especially important with calls around the world, where electron/light speed already adds 150 ms.
I would hope that my call partner acted similarly but unfortunately they nearly never do.
Maybe some future directed microphone and speaker setup in rooms will finally lead to the same comfort without the wire.
Tangent, but changes in the electric field travel at the speed of light (in a copper wire, which is slightly slower than in a vacuum). The electrons themselves move much, much slower. The speed of light is what matters for speed of information transfer.
It is analogous to a pipe of water.
If you increase or decrease the pressure of the water at the input of the pipe, you can detect that difference in pressure at the other end long before the water molecules at the beginning of the pipe get at the time of the change get to the end of the pipe.
Isn't it ~2/3 c thru copper? Roughly equivalent to light-thru-glass. I'm not quite sure who is running hollow-core fiber.
Cat5 is has about the same velocity factor as fiber: 2/3, but Cat7 is closer to 3/4. Coaxial can get even higher.