Roubini has been saying the same thing for years. He's in dire need of some new material. Many cryptocurrencies are worthless, but that doesn't mean they all are. Just be careful to choose the right ones.
This is the exact text of the interview Dr. Doom.
If it's the "exact text", then you need to credit the source, which I assume is
this article. People get banned from the forum daily for not crediting the source. Don't be one of them.