I think the world needs virtual currencies especially bitcoins due to the system of economy right now is failure, system of fiat currency can not protect us from inflation, our system economy right now can not protect us from crisis condition, it is too old to be runned for couples decades later, so must there are new innovations on our economy system and the answer is only virtual currencies to fix all of this weakness.
At least fiat is stable and kindly do not take bitcoin as digital currency just like other are ,its a virtual investment asset and its most profitable than from forex or other investment markets.we need digital currency because of two thing,first speed and second accuracy.
Yea fiat money is stable with losing values on fiat due to inflation, it is broke system our economy and must be revoluted,
the bitcoins has many advantages than fiat money, this system deflation in bitcoins gives us protecting economy condition
to become more better and the world really needs virtual currencies due to it is more better than fiat currencies.
Well we can say everything negative about fiat but at the end of the day, it's still necessary to have it since running exclusively on digital currency, no matter how advantageous it is, has its downsides that will cripple its users if there's no back up.