The problem is Roubini fails to distinguish between the technology and the charlatans that promote it in order to take money from naive and greedy people.
It all comes down to who needs it right now, and who doesn't. If you're pretty wealthy already, and fit perfectly in the current system most people here don't like, there is not even a slight chance for him to ever be seriously interested in it. I have seen plenty of his speeches and interviews, he's a hardcore legacy system shill.
I'm glad that people like him only represent a minority. I'm certain that when the government he's badly praising all the time messes up in more ways than one, and he pretty much is forced towards Bitcoin, he'll lower his tone to the degree that he becomes a supporter rather than a skeptic. As always, in order to truly appreciate what Bitcoin offers, the system Bitcoin is meant to counter has to mess up big time, which it will.
Back in the early internet days the sentiment was somewhat similar. No one needed it initially, it was said to be solely for porn freaks, will become an environmental disaster, etc. Now nearly everyone is using it and barely anyone refers back to the aforementioned points. It's all about use.