The Google app has become an invaluable tool for many people, allowing for the use of the OK Google command to search for things and complete tasks using nothing but your voice. It's only as powerful as its limitations though, which in this case refers to their requirement for having a data connection to gather certain information and issue the voice commands for tasks. In the very near future it seems the Google app will be gaining an "offline mode" for the OK Google commands making it even more useful for people. Especially those who may have need of it when there isn't always an internet connection around to link up to.
As of now the feature isn't live, but a teardown of the apk appears to lead into the presence of this function being added at some point down the road. With offline mode coming, people will be able to soon complete voice functions while offline. Seeing this pop up shouldn't be too much of a surprise as many of Google's other apps already feature an offline mode for various things. What exactly users will be able to do with OK Google's Offline Mode is still yet unknown in its entirety but it's nice to see it being implemented, and from the get go users can probably expect to have access to functions for making calls, sending messages, playing music, and turning on WiFi with voice while offline.
It also appears Google will be setting the app up to notify people when they're connected to an insecure network. If you happen to use an app currently which monitors your security, like CM Security for example, this type of alert is already something you may be used to, but not everyone uses third party apps too often and having this function baked right into the Google app could be very useful for some. Besides what's listed above, the Google app also shows signs of the possibility for issuing a command related to Google Cast, as well as the ability to tweak the brightness and volume of your devices using your voice. There are also mentions of some new Maps interactions, like new alerts for public transit and potentially Maps populations based on a user's current location or recent search results. The Google app also may be gaining the ability to set reminders by voice, and there could be some new interaction with YouTube, weather, and something with attaching money, so perhaps a way to pay or transfer money using your voice.