Definetly in it's infancy. From those very slow and very structured movements you can guess there must be some serious issues yet to overcome before it can go mainstream.
Meh, I'm sure in 10 years it will be cool but right now it looks like a slightly better virtual boy.
Also, can you imagine a virus which makes it cover up staircases or something so if you lose orientation you just fall down or if it covers a sharp object with holocrap and you impale yourself on it? I feel like there's a ton of obstacles in just liability alone with something like this.
Targeting entertainment is undoubtedly a good profit sector, but I'm looking forward to the real world VATS/pipboy/pokedex aspect this shit could give us for everything. Imagine several years deep when a multitude of guides become available for virtually any object you look at. People could teach themselves basic proficiency with their hands free.
Kids wouldn't need a basketball and hoop or jerseys. The lens could cover every base. You could even hololens a referee. More likely they'd play some kind of paintball though. Cops and robbers is just more intuitive. This kind of thing could get young people outside interacting with reality* again. First it has to be cheap and effortless though. I doubt MS is going to be the one with the winning platform, but I'm glad they're putting the effort into the basics.