May be not stupid, but quite odd thing for me:
The commercial relationships on the station.
The Federation has no money, but DS9-station isn't a part of Federation's space.
So, on DS9 there is plenty of small shops, there is "Quark's" and other eateries, were golden-pressed latinum is used. On the other hand, all people can use free replicators to get food, clothes and other stuff.
The question is, from where the Federation people (starfleet officers) can get enough golden-pressed latinum, if they don't get money from their government.
We never see Quark asking for GPL for anything consumed or enjoyed strictly within the confines of the bar. Presumably, Quark is satisfied with whatever non-monetary currency is used by either the Federation, the Bajorans, or just on the station for food, drink and holosuite time. It's only when something is durable and transportable that GPL becomes the preferred method of payment: gambling, wedding rings, auction items, etc. It would then be up to the individual SF officer to convert whatever credits or allowances or barter for services in order to obtain the GPL or initiate an exchange.