Re: Gene Roddenberry's weird rules
It could make sense but they didn't think too much about it when they wrote those throwaway lines. And then they invented latinum as a simple explanation because I doubt many viewers would have been interested in lengthy explanations how the Federation's economy works. It's similar to all the other inconsistencies in the Trekverse.
"Now and then we had a hope that if we lived and were good, God would permit us to be pirates." Mark Twain, Life on the Mississippi