Artboards are like virtual containers with the help of which we can have multiple canvases in a single document. It was added in Photoshop since the CC 2015 version. They act like Folders but you can also place folders inside them.

Games might need objects for background art or illustrations to show inside the game for loading screens. If your game is entirely 3D, you might need concept art designs to show the 3D modellers what to make. You can do this all in Photoshop.