Temis the Vorta wrote:
Note that the 23rd C had a different economic system than the 24th. Kirk was downright frantic to get mining operations re-started in Devil in the Dark, despite the obvious risk to the workers of whatever was killing them. Not very enlightened of him. Same Federation, same Starfleet, the difference is, no replicators in the 23rd C.
I support this theory. Despite TVH making a plot point about Kirk not understanding 'correct change' in 1986, the evidence in TOS that some sort of money does
exist in the 23rd century far outweighs it. Simply the number of times Kirk refers to his officers "earning their pay" is enough evidence for me (though we might
charitably say that it's just an expression...)
The 24th century certainly has forms of currency... but, crucially, Latinum can't
be replicated, therefore it retains a monetary value (whereas plain old gold is completely worthless).