Everybody uses Whatsapp. It is now so entrenched into society that it turned to be part of its popular culture. When people say "I'm part of a group of old car enthusiasts", they meant they are part of a Whatsapp group in which they discuss old cars.
Countless online services and apps were replaced by Whatsapp over the years, from the top of my head: all IMs, customer service apps, e-commerce (specially for SMBs), email and collaboration in general. I can't remember the last time I received a proposal or contract to be signed outside Whatsapp. My attorney asks me to send him all sorts of documentation, copies of IDs and legal evidence via Whatsapp because email is not as easy to use as the IM.
Well, it's lunch time. I got to order my Burguer King meal via their Whatsapp order taking bot. How convenient.