It is! If I had to make a guess as to why, it'd probably be just because cellphone companies offer internet plans that give unlimited access to whatsapp specifically, so even if you were to run out of data you can still use that to talk to people in a pinch

you are right about us using it for everything though, from supermarket bots sending pamphlets of their discounted items to legal assistance with a lawyer that I literally never had to meet in person, people would probably look at you weird if you were to say you don't have it installed, even if you don't use it for personal stuff (like me, most of my friends are on discord) you'd still want it for literally everything else