It is generally wise to take demonstrations of new technologies with a grain of salt. That was especially true for the Microsoft HoloLens – the hologram-projecting glasses that the tech giant unveiled last week – which a small number of reporters were allowed to use for a few minutes.

Microsoft’s demonstrations were highly scripted and completely controlled. The company was cagey about how well the system worked in more spontaneous environments. Recording devices were barred.

The hardware shown to the media was only a prototype, a two-piece unit that included a heavy battery attachment and a cord that tethered the machine to a computer.

All those caveats aside, the HoloLens is wondrous. It blew me away – and it suggests that interacting with holograms could become an important part of how we use machines in the future. The HoloLens isn’t a gimmick. Microsoft has clearly put a great deal of engineering work into this project.

When you put on the device, which looks a lot like ski goggles, you see three-dimensional digital controls – like buttons, lines and pictures – as well as the sheep from the video game Minecraft superimposed on the world around you.

The holograms did not have very high resolution and sometimes they were a little dull, yet they were crisp enough to instantly create the illusion of reality – which was far more than I was expecting.

In one demo, a Minecraft scene was displayed over a real living room. A Microsoft minder asked me to select a virtual hammer (a tool in the game) and start smashing the coffee table in the room.

She wanted me, in other words, to use a digital object to interact with a real one. I did so and was stunned by what happened: before my eyes, the real coffee table splintered into digital debris and then it was no longer there. HoloLens had perfectly erased the coffee table from the environment.

More important than the device’s performance, though, is its apparent utility. The promise of virtual reality is held up often in tech circles these days, but the practical uses have always seemed limited. Microsoft has spent a lot of time thinking about why people would use holograms.

In addition to Minecraft, the company showed three other useful situations. One was a call on Skype, Microsoft's video-calling service. Using the service, I called an electrician, who showed me how to install an electric light switch.

I could see the electrician superimposed in my field of view as I worked on the switch; he saw what I saw because of the camera on my HoloLens and he could draw diagrams in my view that helped guide me along.

In another scenario, one that Microsoft developed in conjunction with the Nasa Jet Propulsion Laboratory, I walked in a Martian landscape that had been captured by a rover on the planet. There was a desktop PC mounted in this demo room showing a two-dimensional map of Mars. When you clicked a spot on the two-dimensional screen, you could look around the room and see a flag in that spot.

In the third scenario, Microsoft showed off HoloStudio, an app that allows novices to design 3-D objects and then to send them for 3-D printing to make them real.

For me, the main shortcoming in HoloLens was its gesture mechanism. To select objects, you look in a certain direction, then tap your finger in the air. However there was a bit of a lag between when I tapped and when the machine registered it and it was also difficult to point precisely. Still, this was an early version, so it should improve.

Microsoft hasn’t yet revealed the HoloLens’ release date or price.

HoloLens will inevitably draw comparisons with Google Glass, the much-mocked computerised spectacles that Google has been peddling over the last couple of years. There are certainly similarities: both devices mix digital images and daily life and both make you look silly when you wear them.

Using HoloLens though is a significantly different experience from using Glass. Whereas Google’s system mostly keeps the digital images out of your field of vision and is thus more suited to be used in public, the HoloLens immerses you more deeply in a digital environment.

Glass is meant to be more like a replacement for your phone – a way to get a quick dose of information at a glance – while the HoloLens seems more like a substitute for the personal computer. In other words, it's meant to be useful. – (New York Times service)