I've seen a preview on FMX and there was quite a discussion on cloud pipeline over the course of a few talks.
I'd say it's certainly the future. How close to it being usable we are is tough to say. The latency is an issue, but that is only a question of paying more for getting studio on a low latency connection (certainly possible in most areas of europe) even without sohonet. There are some areas, where it probably won't be usable even with very low latency like animation. On the other hand I've animated a fair few shots via teamviewer connection to the studio from home a while no super pleasant, I wasn't slowed down too much overall.
The real issue that is a dealbreaker at this point is money. This stuff is seriously expensive. He's talking about $30/h per machine. That is more expensive than the artist in many, if not most places.
That being said, it's super sexy for smaller studios. We're always looking at way to scale up and down quickly and this would be the best way by far.