The majority of times when somebody calls me over WhatsApp, I can't properly hear them and need to hang up and switch to a regular call, which works properly
You or them have some issue with device, whatsapp calls work perfectly fine for past 15 years. If needed you can quickly switch to video, good luck with normal calls.
Back home 5g signal is weak, so my phone does even regular calls over wifi/network, then you are 1:1 with whatsapp or similar apps. No more missed or interrupted calls due to blip in coverage.
Here in Europe I know exactly 0 people who don't have it, even online contact forms of various webs and companies have direct whatsapp contact.
Europe is not homogeneous... I rarely see WhatsApp integration in Switzerland.
But my phone providers support "Call over WiFi", and calls that go through that are crystal clear. But it's curious stuff, if the calls are being routed through my home WiFi (or when I'm on the road: over my data SIM, which is from a different provider), what the hell am I paying them X cents/minute for?
Apple is to blame for many things, but the fact that if whatsapp has access to your contact list you can't start a conversation with any phone number in an easy way is entirely up to them.
This said, it's good to see that apple is slowly adding things so basic that it's baffling they are not there since years.
Could imagine that countries like India the majority of buisneses also have an whatsapp account.
Never tried it, but it seems that calling a regular non-account via whatsapp will still work. But routed through watsapp servers. If someone can confirm or deny that, would be cool.
I either use FaceTime or WhatsApp.