http://dealbook.nytimes.com/2013/11/11/the-rush-to-coin-virtual-money-with-real-value/Here we go again, Ripple Labs is tirelessly promoting their scheme...
Still, the entire world of virtual currencies could be rendered irrelevant almost overnight if law enforcement agencies decided to crack down on transactions. Several state and federal authorities have said that they are looking at how to police the market, worried that the anonymous nature of the online transactions make the currencies attractive for criminals.
Yes, centralized proprietary systems with a single point of failure such as Ripple, could be "rendered irrelevant almost overnight" by heavy handed authorities, no doubt about it. That's why they WILL inevitably fail, sooner or later. Really decentralized P2P currencies like Bitcoin, not so much.