The name is a bit deceiving, as we still can't answer and make calls with most Android Wear devices (some Samsung watches can) but this app does serve a pretty helpful purpose. Wear Speaker essentially lets users answer a phone call from Android Wear just like they usually would, but will instantly turn the phone's loudspeaker (speakerphone) setting on. Allowing users to answer calls and have a conversation without ever touching or holding a smartphone.
The app can be set to automatically do this, ask you first, or even control how loud the volume is set to once a call is answered. However, not all features are enabled unless users spend some money on in-app purchases.