HoloLens is not for games
HoloLens is not about games and not even about VR. It is for augmented reality. Communicating, watching videos or working. And don't get carried away by a trailer just yet. I seriously doubt that you can see your model like the modeller did in the video. It also showed a little about Minecraft, but I also don't think that it will work like that.
For VR there are also numerous tools to choose from, and the most popular is without doubt the Oculus Rift. Microsoft acted a little late and had to came up with an idea that isn't already on a market: a device just for augmented reality. It's worth knowing that any VR device with a camera built in it can work as an augmented reality device too. I can't recall the name, but there's already one in development where you can switch between VR and AR modes with a button.