Over the weekend, Google announced changes to Play Games permissions that are mostly meant for developers, but regular users who game on Android will also see a benefit. Players no longer need their Google accounts upgraded to Google+ to use Play Games and can now automatically be signed-in with a standard Google account.
Google+ is getting further decoupled from other Google services. In the cases of Play Games, new users will get a player ID that better respects their privacy and masks their real name. Existing players should see no interruption and will continue to be identified by their previous Google+ account.
Currently, when users open an app that uses Play Games services, they are presented with a pop-up to log-in. Under these new changes, users will only need to log-in once and from then on they will automatically be signed in for all games. However, users will be able to turn off auto sign-in through settings in Play Games.
On their developer blog announcing the changes, Google lists potential issues that developers might want to peruse through. However, unless a game specifically has features that depend on Google+, there should not be any changes.
These permissions changes will take place throughout the year and Google is giving developers a heads-up. Gamers can probably expect an update to Google Play services and the Play Games app before they begin seeing the automatic sign-in feature.