https://www.theguardian.com/business/2017/dec/30/a-record-breaking-year-the-global-economy-in-10-charts:
"Probably the financial story of the year. Even though there are fears of a coming crash, 2017 will go down as the year of the cryptocurrency. Bitcoin’s rise has been meteoric, beginning the year valued at about $1,000 and reaching almost $20,000 by the middle of December. There have been wild swings on the way, with the currency losing more than a quarter of its value in a single day this month, before staging a recovery. Economists think bitcoin has all the telltale signs of a bubble, with worrying parallels to the Tulip mania of the 17th century, when the price of bulbs crashed in spectacular fashion after a buying frenzy."
We support The Guardian here. The similiarity to the Tulip mania in the Netherlands is striking and should be a warning. Bitcoin is speculation, not a currency. And the most ironic aspect is the reason for the rise: the traditional finance system (see http://digitalization-lab.blogspot.de/2017/12/why-is-bitcoins-price-so-high.html).