GPS works because outside is an enormous, unfamiliar place with tens of billions of destinations. Inside is small, relatively familiar, and even a large building has, at most, hundreds of destinations.
Just watching the demo, it's super cool and super intelligent. But it doesn't look like it can do direction - it can only tell direction after you've walked a certain distance. How will it cope with large magnetic things that move - eg Forklift trucks, vehicles, trolleys, wire cages etc.
I don't buy it. Ikea is the only potential place I could see this being of use, and there's no way anyone's going to bake in an extra sensor to a smartphone on the offchance. Look how slow adoption NFC has seen and that's a MASSIVE problem with multiple applications and a clear financial incentive.