i.e. they track your account balance to more than 2 digits, they just only show you 2 digits.
All 10 of them?
It goes without saying that half pennies are dead. A mill seems to be from the Coinage Act of 1792, which is perhaps a tad outdated.
> A mill ... is perhaps a tad outdated.
Yet you use mills every time you pay for gas. Pointless in that case? Probably. Still used all the time? Certainly.