I sailed the Crown Princess from Ft Lauderdale
to Rome in May and we used USD on board...but
that may have been because we started in the US, but a quick call to Princess or your Travel Agent would answer the question.
We sailed on Crown Princess Rome to Venice and paid our account on board in US dollars. All tours were also paid in US dollars (that is Princess Cruise tours). We will be on the Star on Oct 17 12 day Rome to Rome (Eastern Med & Egypt). Hope you enjoy her.