Up until about two weeks ago - Bitcoin has worked really well. I want to put $USD 2000 in the pocket of somebody I've never met, and neither of us want to use credit cards, or paypal, or pay fee's, or pay currency exchange.
He gives me a hex string, "1LnLfnc3nU3fYAY3DfuPsmqJqFAuRb4p9U".
Presuming, that Bitcoins are trading at $40 USD/ i type at the linux prompt, "bc sendtoaddress 1LnLfnc3nU3fYAY3DfuPsmqJqFAuRb4p9U 50"
15 minutes later, after three confirmations, he sells those 50 bitcoins at his exchange, and he now has $USD 2000.
That's the way it's been working just fine for the last 18+ months, until the recent couple weeks of increased volatility.
I don't see anything inherent in the currency that suggests we will have 10+% volatility every 15 minutes for the for seeable future. Doubling every month, of halving every month is fine, users of the currency can adjust for 2%/day volatility.
That's about the only problem I see with BitCoin as a currency right now. Let's check back in six months and see if we're still seeing the +/- 10% swings per day.