Go to http://www.wbur.org/onpoint to listen to NPR trying to take on cryptocurrency. But be forewarned that it is sometimes exasperating to listen to Luddites pontificate.
First, the issue of trust and security and ransomware is raised to scare people. Theft is possible from any account - Visa or Paypal or your bank and it is also possible from a wallet holding cryptocurrency. A good question might be what layers of security are available and in use at what level of difficulty to crack for any account. I would suggest that cryptocurrency wallet security is comparably secure - perhaps even more secure. That the government assures your bank account is, however, a definite advantage for fiat currency.
Second the issue is "what does it do?" What does any currency do? It intermediates for value. How does it get the value? The same way fiat currency (like dollars) get their value. People agree that a dollar will buy x amount of y stuff. Sometimes the value of a currency is inflated and sometimes it is deflated - by the agreement of the users of the currency. Governments try to manage these agreements upon value, but they inevitably fail. With cryptocurrency, the users or owners of the currency agree on the value.
Third is the question of whether cryptocurrency is speculative. You bet it is! However, it is arguably less speculative than the value of India's currency that was arbitrarily changed by its government last month or Greece's currency or Brazil's.
Fourth, NPR is usually a good source of information that is not hyped or skewed. Maybe, because the host was a guest host, she wanted to jack up her audience and found folks who could sound alarms about a pretty dry subject. NPR used to be a role model of balance and good sense for other outlets - even in its talk shows.
Finally, there is something insultingly ethnocentric about the tone of the whole conversation. Billions of people are "unbanked" and are subjected to wide swings in the value of their local currencies. Cryptocurrencies can resolve many of the impediments to confidence in value and cross-national trade. There is a lot to be said for this potential benefit to humanity, to people who need a more reliable currency that they can manage their their mobile devices. Oh, and the smug guest who is betting against cryptocurrency. I'll take that bet if he'll shape it to compare against adoption of any other worldwide method for exchanging value.