from the johnny law point of view if you will add on it the coin "crucestans are sea species" it becomes message printed on metal medium, therfore it makes the medium an educational book. to make it more legit add isbn number on them. this whole thing because educational books have sales tax only on delivery methods, otherwise 0%. so if you would excheange those books in physical form between each other at own discretion (barter) you would pay 0% in tax.
and they will not be currency, but only barterable educational books.
they would fuck you up regardless, but the law would be on your side.
that said. its bs. this is what matters: