I disagree with a lot of the posts on this thread I'm afraid. My other half is forced to be in a WhatsApp group because it moved beyond the original design (work chat) to become an actual communications channel for issues.
Which is fine if you're full-time and working on events, hospitality etc. But what about people who work part-time?
I have real life examples of people who "miss" serious strategic information or decisions that have been posted in chats in a WhatsApp group during their days off. 170+ posts, and somewhere buried in that is an "update" that someone is expected to pull out, decontextualise, prioritise and then incorporate for future work.
When a quick two line email, sent in a medium that can be easily caught up on in the right way upon return, would be more professional and the right method.
What's App is the perennial comms channel for the "chatty" manager who just loves to dump a stream of consciousness onto unwitting staff that know if they "miss" an update, they can passively-aggressively berate them for not seeing an "update".
I'm not saying all WhatsApp work comms is bad.
I'm saying it should have its proper uses. It discriminates against part time workers. It's not a proper channel for strategy or fundamental updates.