The HoloLens live demo at E3 was amazing, but it didn't do a great job of realistically showing what the hardware can do. Microsoft has since released a promotional video that gives a much better idea of the device's limitations.
For example, this is what the HoloLens marketing likes to show you.
While the person wearing the headset sees something very different. Microsoft is finally releasing video of what you see through the headset, and it tells a very different story.
Again, this technology is amazing, and is far ahead of anything else we've seen in augmented reality. But when you compare these shots...
With what the wearer actually sees...
You begin to see how far HoloLens has to go before it becomes as good as the initial marketing. Remember, the field of view is unlikely to be significantly improved before launch, according to Microsoft's Kudo Tsunoda.
One more example: This is how the device has been sold to us thus far...
And then a look at what you'd actually see while wearing the hardware.
This is a great look at what the technology can and can't do, and it shows how much promise the hardware has in an educational setting while being very honest about the field of view of the device.
Nearly everyone who used the hardware remarked on the limited field of view, and it's one aspect of the technology Microsoft has been loath to address in official videos and marketing, but we're past the point it could get away without showing what the hardware is actually like to use. Now everyone can see exactly what the hardware can, and can't, do. It's impressive stuff.