> Your colleagues... even send you work messages when on the go.
> Your landlord will communicate via Whatsapp, including sending you utility bills to pay.
> The person you want to buy second-hand stuff from communicates via Whatsapp. The real estate agent trying to find you a place to live will send proposals by Whatsapp.
In each of these examples, the other party has something to gain (a client; a bill payment; offloading some work; etc.), which I'd wager is enough to tolerate the minor inconvenience of sending an SMS/email.