[dragonwriter]

> What money do you want to represent, they all have a "atomic value".

This is mostly not true.

> For instance, when working with dollars store cents.

While external transactions often must occur in cents, internal accounts and unit prices often have smaller amounts. If you don't believe me, visit any US gas station and the prices will be in mils, not cents (and will usually be one mil less than some full-cent value per gallon.) Atomic units for financial applications are application-specific if there is an appropriate value at all, they aren't trivially determinable by looking at the base currency.

In some cases you really want an arbitrary precision decimal (or even rational) representation.