Mojang, the Microsoft subsidiary that owns Minecraft, discontinued the version designed for Apple TV last month due to a lack of popularity.
Although they say you can continue to use the App this may change in the future due to an update. For fans Minecraft is still available on iPhone, iPad & iPod touch.
It has been removed from the tvOS App store and the following notice is displayed when you launch the App.
Effective from Monday, 24 September, the Apple TV version of Minecraft will no longer be updated or supported. We’re grateful to the Apple TV community for their support but we need to reallocate resources to the platforms that our players use the most. Don’t worry though, you can continue to play Minecraft on Apple TV, keep building in your world and your Marketplace purchases (including Minecoins) will continue to be available.Mojang
If you purchased the game in the last 30 days of availability Microsoft will issue refunds
While Apple TV is gaining popularity as a great Media Centre it has not taken off as a huge gaming platform with few casual games gaining popularity on the platform.