^Yeah. I'm pretty sure that the Starfleet officers would have to get some sort of money or something to use when they are on non-member worlds.
I don't think there's any evidence for the existence of replicator rations in the UFP, though. The only place where they crop up is aboard the stranded Voyager, where they could plausibly represent funny money created just for the occasion, to maintain special discipline. All other people seem to replicate without concern for payment or limit (even though there are certain "restricted patterns" such as the gun from "Field of Fire"). I wonder... Does unlimited replication improve or worsen the standing of the UFP in relation to the other powers? Are its people for example more corrupt and unproductive as the result? Or more motivated and innovative? Does the presence of consumer replicators add to the UFP industrial capacity, or detract from it? Cardassians seem to believe in domestic replicators, too, although we might be only seeing the dwellings of their privileged upper classes. Timo Saloniemi
Canon doesn't support your assumptions. 'Latinum' is the only substance that seems to have universal trading value on Federation and non-Federation worlds.
Federation credits are good enough on Deneb IV. But Quark can choose his beans when playing his game, and it wouldn't be that strange for him to refuse UFP credits in the "In the Cards" auction. Or for the UFP to ban children from having credits. Timo Saloniemi
Latinum is considered valuable even in the Federation because it can't be replicated. It's hard for us to understand because the replicator really makes our conceptions of the economy obsolete.
Now "latinum can't be replicated" is just as unfounded a statement as "UFP uses replicator rations". No episode or movie makes the claim that latinum would be unreplicable as a substance; rather, it could simply have value the same way copper obtains a value when it is stamped into coins, or paper becomes valuable when one writes a cheque on it. Since latinum seems to be used for jewelry and currency and nothing else, Feds probably wouldn't even bother to replicate it. Timo Saloniemi
The Federation doesn't have the need for currency when you are in Federation itself. They only use things like gold-pressed latinum to make trading with races that rely on currency like system possible. But from what we witnessed the most, Federation ALWAYS relies on trading. Who uses gold-pressed latinum as forms of currency ? The Ferengy. On DS9 Quark would only accept gold pressed latinum for payment most of the time, but when it came to exchange of resources with other races, the Feds used primarily trade.