There is very little difference actually, it's mainly just your manifest entries must be set correctly and you need a special icon for the TV launcher.
However there can be problems navigating when using standard Android buttons because the user needs to be able to navigate using a TV remote or GamePad and standard controls and buttons may not handle the focus shifting properly. This is not a problem for games, or image viewing type apps, but for some type of apps you may need to create your own navigation mechanism by intercepting key strokes.