In General, it is not clear why he decided to speak about cryptocurrencies right now,but nevertheless, Americans will still invest in assets despite everything
I believe it is all about the Libra coin that he's talking about and not really the cryptocurrency but whatever he just said before that he's not a fan of Bitcoin nor cryptocurrency. It is just a call to make a change for their centralized currency for their investors, probably.
I think this is just an FUD spread by a handful of people to drop bitcoin, we know that lately bitcoin is on the rise. This triggered a handful of people like Trump to drop bitcoin, but unfortunately they were not strong enough to drop it.
I don't care what the man talks about, he always makes decisions that can change an economy. But here he can't do anything because the central policy that he has has no effect on decentralized bitcoin.