No one I knew used WhatsApp or signal (I’m in the US). However I just finished a project with a customer spread between Middle East, Singapore, and India. They ALL used WhatsApp and asked us to use it to communicate with them.
So definitely seems to vary in popularity depending where you are located.
I quit all social media and that included WhatsApp, about a year and a half back. Everyone is fine with me leaving social sites but how dare I leave WhatsApp? They look at me weird for that.
Surprisingly though, Signal is slowly gaining popularity among the smarter crowds.
So definitely seems to vary in popularity depending where you are located.