At an old workplace (Traditional engineering consultancy) we used it to show prospective and current customers walkthroughs of their projects.

Take a revit model, add some textures and you've got a great demo.

> I always wondered what the enterprise customers were using it for.

There are some military training research projects that I came across in a previous life. These VR apps haven't supplanted traditional PC-based training sims, though, although these are often based on commercial game engines rather than custom sims.

The demo apps that microsoft shows probably are what they're using it for. If you look at the microsoft store for/on the HoloLens you'll see a bunch of training and communication apps.