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....
Why should it take hours for my Bitcoin client to sync (and therefore for me to do anything with my Bitcoins) because people want to encode URLs in the blockchain?
In a few years, it could take days to sync a new client. What kind of banking system would that be?