It doesn't seem like it would be any more dangerous to use than a regular rotary cutter, but as others have pointed out, the blade doesn't retract when not in use. I think I could get used to not seeing the blade - sort of like not looking at your needle when you're sewing and just trusting it.
But I don't jump on to new things unless there's a clear advantage, or I'd have drawers full of stuff that I don't use**, and it doesn't really seem better than an ordinary rotary cutter. For people who have trouble gripping due to arthritis or other causes, it might be helpful. I hope people who try this will post their experiences, since it's hard to tell from just watching a video.
** Instead I have just one drawer full of stuff I don't use.