I am currently working on a game with Google play games integration. So far everything works fine. Users can log in, achievements and leaderboards are updated. I also implemented snapshots. In the game I want to give the user the possibility to delete all his data. With snapshots this works well but I can not find a way to remove the user data from achievements and leaderboards.
For testing unpublished games, you can manage the leaderboard data and perform various operations such as clear / reset leaderboards.
When you are live, you can hide a user so they do not appear in public leaderboards. This will not hide the player from their own leaderboards though.