Been following this thread for a while. I've had at the Apple Watch since S0 and although initially I did reply to iMessages using the watch I just found it too cumbersome and the voice recognition was not good enough so I stopped. I can't see how that process would be any different with Whats app. Overall fine to send quick emoji type messages but otherwise pretty much useless for a proper message. So much easier and quicker on the phone. So overall the presence or lack of a Whats app app is a moot point.
Also even without a dedicated app the notifications of whats app messages still come though fine so one can still read those just not reply to them.
Also even without a dedicated app the notifications of whats app messages still come though fine so one can still read those just not reply to them.