People have been (incorrectly) predicting the demise of bitcoin for the past five years. Despite criminal enterprises such as Silk Road, and security scandals like Mt.Gox the currency survives because it offers a lot.
Bitcoin is no more a ponzi scheme than any other currency is. The gold standard is ancient history; all that gives those polymer sheets in your wallet any value is the mass hallucination of society that dollars have value. Governments restrict and ease the supply of money. Quantitative easing, or the printing of money - is used to devalue everyone's money a little bit, so that they can offer stimulus. It is a form of hidden taxation.
Us little people have no say in how our money gains or loses value. That's up to the big shots who have the ear of the Bank of Canada. My retirement which is in Canadian Dollars has dropped 30% in a couple of years. That seems pretty volatile to me also.
With Bitcoin there is no ability of a government to print money - and devalue everyone's currency as a byproduct. Bitcoin is minted at a steady rate of 25 bitcoin every 10 minutes - with the rate halving every 4 years. All 21 million possible bitcoin will be minted (or mined to use the bitcoin vernacular), by 2150. The people who get those 25 bitcoin every 10 minutes are the folks who provide the computing resources to process all of those transactions. There are no huge data centers like Visa or Paypal has.
Bitcoin, like gold, will naturally appreciate against currencies that devalue themselves. It's volatile right now because the transactional volume is rather low - much like thinly traded stock. The purchase of a few thousand dollars worth of bitcoin will visibly move the currency's price.
Another thing that gives it staying power around is it is useful. My last trip abroad I used bitcoin almost exclusively. I transferred Canadian dollars from my bank account into bitcoin, moved them to a Philippine exchange, and then withdrew them as Piso from ATM's throughout the country. No Western Union fees, no Visa network fees, no 2.5% exchange commission - just the pure exchange rate, a one dollar fee in Canada, and 7 cents in bitcoin transaction fees for the transfer between the exchanges.
I was able to pay my phone bill in bitcoin. If I lived there, I would have been able to pay my cable, electricity, water, and online shopping in bitcoin.
People around the world who have no banks, but have mobile phones are using bitcoin extensively.
This Ted talk is a really good introduction.
https://www.youtube.com/watch?v=WI1pbHi1fww