It looks like Google has been aggressively planning to integrate SMS and MMS capabilities into its Hangouts app for Android.
Recently, Android Police said that the app would be soon getting a new Hangouts update version 1.3 that will enable integration SMS and MMS within the app itself.
Apart from SMS integration, Hangouts app is also said to get support for video sharing via Hangouts protocol in the upcoming version.
With the new update the messages sent via SMS will show "via SMS" next to the timestamp so that you can always figure out which protocol was used for each message delivery. Users can also request delivery reports for sent SMS messages. MMS picture messaging is supported as well.
One can see the leaked screenshots clearly showing the SMS and MMS integration in the app. Apparently, the feature looks like it is optional.
As of now, there is no information pertaining to the release date of the new version of the app. However expectations are that the new version of the app will be released with the all new Android version 4.4 KitKat and the purported Nexus 5 device.
Before coming up with the Hangouts app, Android smartphones used Google+ Messenger, Google Talk, Message and Voice. Then came Hangouts which integrated Messenger with Talk. Now Google has integrated the Messaging feature into the app as well. Soon, only the company's Voice service will be left alone. And who knows, Google might also integrate Voice into Hangouts in the future.