I think you're using legitimate to mean "legal and most reasonable people would be okay with it" whereas the post you're responding to meant "legitimate" to mean an actual real technological advancement that wasn't doable with previous technologies
A government that fully supported an actual digital cash that was untraceable (perhaps this is best done with crypto, but you can do it without a blockchain) would serve the same purpose.
But anonymous London shell companies have been available for years!
Of course, apparently fees on bitcoin are so high that buying a dime bag there isn't useful, either.