It is a legal minefield and would drag govt.s into courts for years trying to figure of out fine distinctions in crypto-technology that politicians have no clue about.
Change in the legal system happens very very slowly, and the internet moves lightning fast. It will take politicians and judges years to even get their head around what a p2p cryptocurrency is in the first place, and by that time their 10-year old daughters will be using Bitcoin as in-game currency for MMOGs.