Is it normal to be approached

[FraughtwithGin]

for more senior roles via WhatsApp?
I was contacted on Friday, which took up about 90 minutes.
CV submitted, have already had several WhatsApp exchanges with that person today, plus a brief call from someone else.
I must admit for the first few messages I wondered if it were some kind of scam, but they were able to furnish me with proof to the contrary (not that I revealed my cynicism).
Is this a new thing? I actually find the WhatsApps quite irritating because I only use this medium for personal/family communication.
Anyway, quite happy to proceed as I am at a loose end currently and the daily rate is excellent, so let's see.

We've been living since April in two different country houses waiting for a delayed house purchase to go through in a new country with no mobile signal, so all of both of our work calls have taken place on WhatsApp, though we'd both purely used it for personal calls before that.

How have they accessed your number? Is it on the company website? I don't have my number published apart from switchboard.

Any contact from recruiters is via Linked in / email (bad) or direct switchboard.

They had a copy of my (old) CV with my mobile number on it. They said they found it on some site I had never heard of. My CV is only available online in one place. I am a freelancer.
Anyway it appears to be legit.
Just surprised that the initial contact was via WhatsApp not e-mail or even a telephone call.