From my experience a lot of people will not hesitate to contact you via WhatsApp even in a professional setting if they can get hold of your phone number. After this happened several times to me I made sure to have a separate phone for business where no messengers or any "social" apps are installed. The funny side of this behavior is your client messaging you via WhatsApp but forgetting their profile picture shows th…
I’ve never understood the appeal of WhatsApp: it requires a phone number (so it’s useless or hard to setup abroad, and it’s tied to a very personal data), handle very poorly wifi connection (somehow it seems to only update when connected over 4G) and force me to download pictures and videos to see them, trashing my photo folder in the process. It also has no killer features in comparison to any existing messaging app…
In 2011 I was a student in university and I had friends in my circle from Erasmus so they kept their phone number from their own country. In 2011 it wasn’t even free for me to send a sms to people from my own country so I couldn’t even imagine sending sms to people internationally even though they were physically in the same city as me.
Well one day a friend told me to download WhatsApp. So I did. All it wanted me to do was verify my phone number and that’s it.
Now suddenly all of my friends with smart phones could just sms me for free. And I could sms them back too. For free.
That was the value of WhatsApp. The fact that all you needed was a phone number, which you already had saved in your phone. Now instead of opening your phones messages app, you just open whatsapp.
There was no extra step of signing up for a new account or telling people “search for my name on Facebook my profile picture is blah blah.”