behavior and speculative investment.

Neither of these functions offers much of an incentive for ordinary users to exchange their existing currencies or payment mechanisms for Bitcoin. Because of its important role as an investment vehicle, much of the development effort for directly interacting with Bitcoin has been put into developing interfaces for managing currency-trading exchanges, but considerably less has been put into its use for everyday activity. The massively distributed computational architecture of payments processing for Bitcoin means that delivering proof of payment is relatively slow, again limiting its potential for more routine forms of exchange. These forces— and they all arise through deliberate design choices—conspire to mean that Bitcoin is not currently used much as a form of regular exchange. It seems unlikely to replace the regular forms of government-backed (known as fiat) currency that we typically use to make payments. Bitcoin is not unique in how these kinds of design choices affect the use and usefulness of digital money systems, but by understanding both the ways in which people use money and the ways in which different system configurations afford different opportunities for interacting with money, we can look to support different ways of transacting with money.

There is a huge diversity in the
possible forms that money may take
in the future. It is likely that a new
ecology of systems will develop around
niches in the financial infrastructure,
each with its own opportunities for
interaction design. However, there is
an elephant in the room: the influence
and interests of national governments,
and in particular, the role of central
banks in economic control and
management. Their interests lie in
ensuring financial stability via control
of the money supply. Reductions
in financial liquidity, impacts on
inflation or deflation, opportunities for
fraudulent behavior, and so on, have
huge potential to damage national
concerns, and so the regulatory
environment for financial technologies
is under continuous review and tight
control. Nevertheless, central banks
themselves are taking an increasing
interest in developing digital
currencies based on the distributed
ledger technology (DLT) that Bitcoin
is built on that integrate with their
existing forms of fiat currency. That
they are doing so has ramifications
for all citizens and our daily lives due
to the pervasive influence of money
across our individual, social, and civic
activities. Getting the design right in
this instance is critical to much of what
we take to be otherwise unremarkable
and ordinary. Indeed, as Andrew
Haldane, chief economist at the Bank
of England, states:

Whether a variant of this technology could support central-bank-issued digital currency is very much an open question.

So, too, is whether the public would accept it as a substitute for paper currency.

Central-bank-issued digital currency raises big logistical and behavioral questions too. How practically would it work? What security and privacy risks would it raise? And how would public and privately issued monies interact?

These issues are of core concern to interaction designers as much as they are to economists.

Outside of the industrial-scale interactions carried out in the wider banking sector, the majority of the financial interactions that involve money are relatively small-scale. Buying a car or a house are important but irregular events for most people. Consider your own daily spending, for

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