WhatsApp is very common for smaller simpler projects, and I'm pretty happy with it.
My main communication related complaint is when it just doesn't happen at all.
Plans change and nobody tells me so I work on cancelled features, only one person actually knows what's happening and they're busy so you don't want to ask them about every detail, minutes are not taken at meetings.
I also would prefer calenders be managed better. Google shared calendars are amazing, I'm sure there's something similar people like for bigger projects where some people use apple... But nobody seems to really see the need for anytime like that.