I don’t just mean socially speaking. But for contacting services and stuff. My car insurance company only accepts reports through Whatsapp or through calling a guy to come look at your face for a fee.
In some different countries, WhatsApp is how people conduct business. I am anti WhatsApp in my regular life, but I used it with a VOIP number when I was traveling abroad.
It’s one thing to tell your friends and family you use Signal, you can’t tell literally every business. Well, you can, they just won’t to do business with you.