Well it's implied that holodeck time is inherently limited. Not everyone has one. The Enterprise (D) only had a handful for over 1,000 people. On DS9, you had to rent them at Quarks.

This brings up another point that is never addressed. Quark runs a casino / bar / futuristic (adult) movie theater expressly for profit. It's also implied that Star Fleet members don't get paid because they are members of the federation. Yet these same officers are often seen frequenting Quark's place. Where did they get the latinum (money)?

That's a contradiction in the show. In some places, they laugh about the concept of "money", and in others they clearly have and use money like you point out, and talk about "Federation credits". It's one of the really annoying things about Star Trek, because they clearly didn't think it through.

For the episodes where they aren't dealing with extra-Federation societies like the Ferengi, it makes perfect sense to not talk about money on the ship. It's not much different than being in the Navy today: if you work on a US Navy ship, you don't have to pay to see the doctor, or to go to the mess hall and eat, etc. All that stuff is free. It's part of being a crewmember on a ship. It's the same on the Enterprise-D (or even Kirk's Enterprise), except they have even better benefits (e.g. replicators; on modern Navy ships there's I believe a little store where you can buy extra goodies they don't give away in the mess hall, but with replicators you wouldn't need this). Gene's idea of modeling Starfleet on the Navy worked out pretty well this way for a while, until they started dealing with jurisdictions outside of Federation control and then they had to retcon stuff like "gold-pressed latinum".

The Federation is a socialist society internally, but presumably still uses money/valuable commodities for trade with other civilizations.

(Honestly, they totally hand-wave why you can't just replicate latinum)

Economics is never addressed in Star Trek, but I could see an administrative solution to such issues. Inside Starfleet there is little to no money, as replicators are readily available. The power supply and replicators themselves would be there anyway, so giving the crew access is a freebie. And the civilian society on advanced worlds would be similar, with manufacture of material possessions too cheap to worry about.

On worlds still using money with which Starfleet interacts, the local administration could simply make an arrangement with the local purveyors of desired goods to cover their tabs, perhaps at least partly in trade. The needs and wants of the Starfleet crew members would likely be only social, such as hanging out at the local bar.

There would be temptation by the locals to pressure the crew-members to give them replicator-made goods, and by the local proprietors to lie about bar tabs, but its nothing our current system doesn't deal with.