Update:
Remember a few years back when a lot of countries decided that the perfect way to dissuade people from smoking was to remove the colorful designs from the cartons and replace them with white, neutral packaging? Australia was the first country to implement them on a wide scale, and now a different chain of shops in Australia is doing the same thing . . . with video games.
The shop in question is Target Australia, the chain of shops who previously pulled copies of Grand Theft Auto V from shelves after a social media campaign. This same campaign also drove Kmart Australia to also ban Rockstar's crime game from their stores. If you want to see what plain packaging for video games looks like, feast your eyes on the following picture posted by neoGAF user nephilimdj:
What's interesting about this is that Target Australia made the choice to switch to plain packaging for 18+ rated games at their own volition, without government interference. These same games can be seen with their original covers in other game stores on the continent. The fact that shops aren't allowed to sell 18+ games to minors anyway makes you wonder who the plain packaging is for; for the kids so they know which games are off limits, or for the store employees so they think twice before selling a copy of Dying Light or Call of Duty to the 13 year old in front of them.
Australia is a strange country where video games are concerned. Apart from the aforementioned banning of Grand Theft Auto V from Target's shelves, the country itself is very quick to ban any and all games their government deems unfit for classification. Previously games like Manhunt, Postal 1 and Postal 2 and Hotline Miami 2 were banned from sale in brick and mortar stores, with some of them only available via the Steam Store.
Quick Take
I don't see why this is necessary. Target's employees should be the gatekeepers here that keep underage kids from getting the games not rated for their age group.