From Fallen London Wiki

Big L for the Numismatrix. Surely the person with enough of a hyperfixation on currency to imagine herself as Mr Coins should know about market-day scrip; for centuries, it's what people without much gold or silver to their names would use to buy and sell their goods at bazaar, only settling up the outstanding balances in precious coin at the end of the day.

Perhaps her theory of value is more like that of Mr Stones? That money is only money if it can be used to preserve and store value over long stretches of time?

Or maybe she's just racist against LBs. Ratcist.