whilst you are correct that the definition (which could be amended) includes that it is electronically created
a) it was clearly a currency for many centuries

b) Obviously it was digital

dig•it•al (ˈdɪdʒ ɪ tl)

adj.
1. of, pertaining to, or resembling a digit or finger.
2. manipulated with a finger: a digital switch.
3. having digits or digitlike parts.
4. of, pertaining to, or using data in the form of numerical digits: a digital recording.
5. displaying a readout in numerical digits rather than by a pointer or hands on a dial: a digital clock.
6. Computers. involving or using numerical digits expressed in a scale of notation to represent discretely all variables occurring in a problem.
7. of, pertaining to, or using numerical calculations.
8. available in electronic form; readable and manipulable by computer.
n.
9. one of the keys or finger levers of keyboard instruments.
10. a digital device, as a clock or watch.

c) it was virtual

d) it was a medium of exchange

So we could consider the tally stick a digital currency  pre dating electricity/internet

http://en.wikipedia.org/wiki/Digital_currency

Apart from the "electronically created" part of the def. which was not an option in 1100A.D.  it fullfills the virtual and medium of exchange aspects which are arguably the more important part.

http://en.wikipedia.org/wiki/Medium_of_exchange

Digital currency is a form of virtual currency or medium of exchange

and its aims and effect, to remove power and abuse from money changers/bankers is consistent with the aims of todays virtual and crypto currency  

additionally the conclusions of the author in the  2006 book may well be altered with the rise of cryptos since 2009