I think everybody should sit down and figure out what it is they they would/do use WhatsApp for. If the majority of time is spent doing productive things (Torah/Chessed/business), beautiful. If the majority of time is spent on at best wasting time, at worst loshon hara, bizuy Talmidei Chachomim, and abizraya di’Arayos, then you have a serious problem…
(And honestly, which group of people do you think is bigger?)