A common use case of augmented reality (and virtual reality too) is the visualization of models that belong in the real world but aren't there yet. For architects, these may be called preconstruction renderings. For interior designers, they are called visual presentations. Virtual reality is useful when you need to transport the user to this other space virtually. Augmented reality is useful when the user is already in the space and you want to show them something different, to augment the environment.
In addition to design, this also applies to marketing and sales. Ikea and Wayfair, for example, are furniture retailers who offer AR-enabled mobile apps that let you visualize potential furniture purchases, placed in ...
