With a simple app update, Google has just fixed one of the biggest gripes with the Hangouts Dialer — it's now actually identifying itself to the system as a dialer app. Prior to today's update, you couldn't quite fully replace your normal phone app with Hangouts because if you ever needed to initiate a phone call from another app — like a restaurant in Google Maps or a phone number in a text message — it would always kick you out to the phone app, with no choice to choose Hangouts.
Now when tapping a call link or phone number in any other app on your phone, you'll get a familiar dialogue giving you the option to choose between your phone app and Hangouts Dialer — and you can even choose to use Hangouts as the default from then on. When a number is tapped Hangouts launches to the dialer tab and handles the phone number from the link perfectly, just as we all wanted from day one.
Just as importantly as relieving the prior frustration, this is the final nail in the coffin for the Google Voice app for those who have gone all-in with Hangouts for calls. Now if you choose to make all of your texts and calls via Hangouts, you have no need for the Google Voice app to route calls via the phone app any longer.