The advantage of Orbit Wheel skates is that you can slip them into your backpack. That's nice. But how are these skates any improvement over a skateboard otherwise? Or inline skates? The site says "you don't need to fuss with buckles and flaps" which is one of the advantages of skateboards, but it's a safety feature on skates. What happens when you wreck on Orbit Wheels? Skates should either be impossible to slip out of (blades) or very easy to step off (boards). It's hard to tell with these. They couldn't possible stay on well enough to execute high jumps safely, and if you try to land on them, you've got two to deal with instead of one board.
One of the advantages boarding has over blading is the ability to push off with your foot. You can't do that with these. Skates are propelled by pushing both left and right, which you can't do with these. You're riding sideways like a skateboarder, so you'd have to propel by pushing forward and backward. Sure, you can learn to do it, but it seems like a combination of the main disadvantages of boarding and blading- riding sideways and staying wheeled.
When I see a video of someone doing aerials and flips like a skateboarder, or spins and arabesques like a skater, it may change my mind. But as of now, I don't see these as being much fun.