As a pilot, I'm really sorry about the state of infrastructure at the destinations, but we need fax or phone sometimes.

For context: Imagine a crew room, with an old yellow looking windows 95 machine as the only "IT service" and only GSM-speed (or no reception at all) mobile internet in the area. The machine doesn't really work, or is on a dialup connection (yes this still exists).

These are the cases where we use the phone, or write the plan manually on a form and fax that. The phone has a high risk of mistakes, because you're reading lots of numbers and codes so it's easy to misunderstand one.