It still sort of makes sense, as others mentioned for working with non-federation entities. But the money-less thing makes more sense to me if you have replicators. The only “cost” there is the material you use for the replicator. So even if you had a money society, things --should-- be dirt cheap since most even outside the federation should have a replicator.

In some ways, I think it’d be harder to have a money and market system when replicators exist.

I assume replicators have some non-trivial energy debt, too. If my memory were better, I might even remember an episode where replicators couldn’t be used because they were on backup power. Like, compared to warp, it’s nothing, but if the warp core or main dilithium generators are offline, replicators don’t work.

I know we’re in tenforward, but another good post-scarcity-except-when-not is Iain Banks’ Culture. Intelligences still trade, but it’s more information/skillset/favors based.