I have not had someone ask me to use WhatsApp in nearly ten years, I deal with people on iMessage every day...
Africa runs on WhatsApp.
Went to South Africa on vacation last year. United lost our luggage on the first leg of the trip, which then became South African Airways responsibility to sort out because they handled our final leg.
I communicated directly with the SAA baggage agent over WhatsApp. Then communicated over WhatsApp with the courier delivering our bags . Best customer service ever.
Are you in North America? I’ve found this to be true in the US, but not in Europe or Asia.
I can predict the country you live in with reasonable reliability from this comment alone.
This would not be true most places outside of the USA and maybe Canada. In a few countries/regions it might be a different third-party messaging app.