Doing so sticks billions of transistors between A and B, all of which have to work perfectly billions of times a second. If you just run fiber, you need to put

Doing so sticks billions of transistors between A and B, all of which have to work perfectly billions of times a second. If you just run fiber, you need to put an amplifier in every 50km or so, other than that it’s all just buried glass. The fiber is already there, and it gives you guaranteed capacity, even during a major power outage. And it guarantees no one is changing out a switch or a router at a bad time, etc. It’s just a lot less to control and to go wrong.