A primary source is fine but not to back up debatable technical information. Wikipedia is not a technical manual, it does not need advanced technical details of Bitcoin. The link to the bitcoin website is there so if people wish to get into the technical details then they can follow the link. If the technical details of bitcoin are only on the bitcoin website then we should not slavishly reproduce them here, that is not what wikipedia is for. See WP:NOTMANUAL, this is a pillar of wikipedia.