Currency is an important economic good in itself. Money helps to facilitate efficient division of labor by providing a common medium of exchange to which all other resources can be compared. Large multi-way deals would yield the full benefit, but are difficult to negotiate. Also, in a pure barter economy, an economic agent needs to have available to it an exchange rate for every possible pair of goods it would need to trade.
Money lowers the computational overhead of conducting commerce.
Easy portability and divisibility are desirable but not vital characteristics. Citizens of cyberspace would prefer that money also be in the form of electronic information. The problem with digital money is balancing the demands of scarcity, fluidity, and anonymity. Digital information can be transmitted instantly, but it can also be duplicated without limit, making forgery of purely digital banknotes an important concern. The problem of anonymity has not been taken for granted until the last decade or so, during which much of the motion of money in our economy became electronic.