Seems to be the platform for the next level of interaction with Amiibos.
Not exactly a core part of the NX, as some people are thinking here. By "core", i mean is not something that will be included whit the base hardware.
i think the success of the idea rides in if it will actually have the capability to project images. An by project, i don't mean the Hologram type of projection which seems to require quite a lot of space since we are some years behind mass consumer air projection devices.
It would not be as interesting if the device is just the sensor with a limited 360 degree tracking range and the user just puts some surfaces or overlays with fixed designs for the sensor to rest in the middle. That would be a half way realization of the concept.
However say, take something like Mario Party. The device projects and animated board over a table and can track the positions of Amiibos figures over it. Or for an Amiibo card battle game where the device projects the interface over a surface and detects which cards the player is using. Not to mention rhythm games.
They could also replicate Wii U type experiences with dual interfaces, where the TV screen and sensor compliment each other and add some enhanced degree of inmersion. As a hypothetical (not necessarily practical) case, imagine having the option to use the sensor in a Zelda. While you play the game normally on the TV screen, having a cloth map displayed on a table near by or on the floor that display a variety of information in real time. Or using it in segments like the ones in Twilight Princess where NPCs showed Link locations and points of interest in the maps.