Messaging apps are far better to use and work across borders without added cost.

Trying to get people to install and use them can be frustrating. Some are regionally popular, like WhatsApp in Europe, and most people I really want to talk to use Signal, but the most popular messaging app in the US is probably iMessage, and only because Apple integrated it and SMS in a default app. Google started to do the same thing with Hangouts, but dropped the ball.