This also requires a functional computer, a steady power supply for it, and an internet connection reliable enough and fast enough to handle it. In large portions of the globe, this is laughable.

A telephone needs a couple of wires and can be powered remotely (those of you who still have basic landlines will recall that they often keep working when the power to your house is out), and is a fantastically simple technology to repair and maintain.

In some parts, mobile phones (AKA cellular phones, AKA handy phones) are leapfrogging landlines because they require even less physical hardware and maintenance - it's not the case that everyone has one; rather, someone has one and sells use of it. People use it to make voice calls.