The key fact here is that Ron and Shamir's paper got nuked by an amateur on Reddit within minutes of it's publication. Turns out the public ledger makes it tough to fabricate anything - even when you're sponsored by Citi Foundation, the charity arm of Citi Group, one of the world's largest banks, as was the case with Ron and Shamir.

I'd rather buy BTC than USD because it seems easier to prove my innocence if I have nothing to hide.