This phrase is misleading and cant find anything to support it. The only comment I knew he made on bitcoin was what anyone or country leader would have said for a speculative and volatile market like cryptocurrency. He does not want to subject the populace to a risky market like cryptocurrency, where most may not even learn the trade and invest on president approval alone. Every investment has its risk like bitcoin but this especially may not be advisable for those that cant take the risk and learn as well.