I guess I don't see what the big deal is. My Bluebuds have an answer button. It's connected to the phone, I just look at my watch, see who is calling and answer with my bluetooth headset. I never have to touch my phone and the watch just asks as a display.
If I want to initiate a call just use Siri from the headset.
This is what I found after further testing. If I answer or initiate a call with the watch it will not use my earpiece.
They should have it use the earpiece if it's active when initiating a call from the watch though.