Earlier quoted context omitted.
It's presumably only temporary measure, and only present in the reference client. Anything below four decimal places is completely worthless at this point anyway; do you really have a use for being able to send 0.01c USD?
If micropayments are ever to be possible, sub-penny transactions need to happen. If 10^6 people send you $0.001, you get $1k....
Even if payment processing costs weren't an issue (which would cause many more small unbatched transactions in gov currency, similar to the crap being dumped into the block chain... banks have to log gov currency transactions for auditing purposes), whatever the cost of individual transactions, if you have a payor who owes you $.001 over a billing period, you've done something wrong. They'd be just as willing to pay you $.01 as $.001.