With all the buzz around Android Wear a little more recently with the devices that had shown up at IFA and the recently released Moto 360, people might be struggling to find what they can do with their newly prized smartwatches. What might be on everybody's minds right now though is the Hangouts Integration with Google Voice, which happened briefly a couple of days ago only to have Google revert the handful of users back yesterday and then back again today. Now that things are officially official, you might be like some of the other users out there who are sporting one of the available Android Wear smartwatches who also are pretty heavily invested in Hangouts and Google Voice as main messaging applications, and wonder if the combo plays nice together.
Hangouts has been compatible with Android Wear from the beginning, but one thing that people might have been waiting for at some point was some integration with Google Voice. At long last, with the merging of the GV app into Hangouts it seemed that you might be able to send GV messages through your Android Wear watch, and you can, but the message apparently still sends through your carrier number and not through your GV number, at least for some users.
A thread has started on reddit that seems to point to some users not having the ability to send messages via their Android Wear smartwatches using their Google Voice number, something that you think you'd be able to do now with the Google Voice merging into Hangouts. While this might be just an isolated case with this one user, or maybe a few, in theory it should work just fine. If you had the message pop up in the Hangouts app asking if you'd like to merge your Google Voice account into Hangouts(which includes SMS and voicemail as well as calls)sending an SMS through Android Wear uses Hangouts, and so the message should send through whatever number you choose. If you go into Hangouts settings and choose your GV number, that should be the number that people see when they receive messages that you send via Android Wear. That is how it worked for me personally in a recent test after reading this thread, and at least one person commenting in the thread said they had the same experience when sending a message from their Moto 360. What is likely the case for the OP, is that they either didn't merge the two apps yet, or didn't set Google Voice as the preferred number to use when sending messages using Hangouts. Long story short, Hangouts messages sent from Android Wear should use Google Voice if you select that number through settings.