The IKEA app is AR because it adds objects that interact with the environment. This app doesn't. Furniture in the IKEA app is registered in the real world's coordinate system to create an immersive experience. It is a form of interaction that requires tracking to allow the intended use.

Interaction with the real world doesn't require much more than stable tracking as long as it is used the right way. If this app allowed you to walk around while you play it (does it? I haven't tried it) and interact with your environment in that way, i wouldn't mind if people called it an AR app. But if it just adds a video background to a game that would work perfectly fine without one it's just using resources and draining battery without any reason to do so (as seen in countless games that track a phones orientation without calling themselves AR apps).

AR by most definitions isnt simply using sensor fusion, optical see through displays etc.. It's not the tech but rather the application of that tech. Just as GPS is not navigation tracking isn't AR.