I think those “standard currencies” don’t fit into the unique setting Oort may have later. May be 100 shards become a crystal and 100 crystals a gem. Let it be more special without losing the functionality
i can also live with that since oort stones and shards seem to kinda power everything they cant give a logical reason to. you just need some form of generally akknowledged currency or you cant have anything reminding even remotely of a stable economy
The economy will become stable, some will barter, some will stockpile different currencies, some will travel and trade, some will place orders for goods, some will set up shops- and some will operate within an informal economy.