Insular US and Canada does not get Whatsapp, if they aren't interacting with people outside of those countries.
But the other Americas, Europe and Africa are so heavy on it. It really is becoming the platform that you see in Asian countries for business, which Zuck had hoped he could have. Clout and reputation for business is all on whatsapp for many people. Compared to websites and public pages from decades past, which are still indicators of legitimacy in the US. Luxury watch dealers just post on their whatsapp story when something new comes in, and its sold in minutes. At the other end of the socioeconomic spectrum, people post sneakers they get in stock right onto their story and its a mad dash to obtain it. Professional group chats highly active for private equity deal making and collaboration, organic group chats created on the fly. Location specific group chats existing in perpetuity.
I spend almost all day on it now, out of necessity. And I like how utilitarian it is, it doesn't need to "wow" anyone with UI bells and whistles and they are completely invisible if you are not part of groups that use whatsapp.
I don't like that it forces you to share your phone number, but the etiquette seems self-enforcing. The chat size limit is a blessing and a curse, but they probably shouldn't change it.
Its not about what other chat applications can do, its about what happens.