Earlier quoted context omitted.
Lead is useful. Even gold is somewhat useful. Bitcoin is an asset that’s neither productive (stocks, bonds, land) nor useful (oil, wheat, lead). That’s quite unusual.
You can buy Bitcoin worth 50k USD in one country, cross the border and sell it in another, with no documents required . This is useful for a subset of people .
There is no reason that same pair of transactions could not have occurred with British bonds.