Separating it is fine, I don't want it in the Hub. I don't want anyone to tell me what I can and can't have in the hub or what ringtone I have to use. To me that is far more important than being able to add another method of talking to someone via voice using data rather than minutes.
And what's with the awful way the call answer button is displayed? Why no conformity?
If whatsapp are serious they should fix these issues before releasing software.