It's hard to consider float anything, but a hack - and certainly something to keep away from discrete domains (countables).

I'm a little more curious on the suitability of using integers for money though (integer number of pennies). I suppose there are cases (and rules) concerning fractional pennies? Like in the case of percents of interests, often given by the year, accumulated[1] by the month?

[1] that's probably not the correct term in English.