Also see Trump's Twitter tantrum in this context
"Cryptocurrency backers found a silver lining in President Trump’s attacks on bitcoin late Thursday.Bitcoin Backers Welcome Trump Attack: At Least He Notices Us | WSJ [Apple News+ link]
In three tweets, Mr. Trump said he is “not a fan” of cryptocurrencies, declaring they aren’t money and that their values are “highly volatile and based on thin air.” Unregulated digital assets, he said, could “facilitate unlawful behavior, including drug trade and other illegal activity.”
Still, his remarks were welcomed by some in the industry: While U.S. authorities might remain wary of digital currencies, they say, the attention shows the industry’s growing importance.
“I dreamt about a sitting U.S. president needing to respond to growing cryptocurrency usage years ago,” Brian Armstrong, co-founder and chief executive at Coinbase, a U.S. platform for buying and selling bitcoin and other cryptocurrencies, wrote on Twitter. “First they ignore you, then they laugh at you, then they fight you, then you win. We just made it to step 3 y’all.”"