We created money because there are special laws about "money" that don't apply to less fungible forms of "property."
However, in the referenced question it's unclear that any such special characteristics are involved, so it is presently tagged property.
As examples:
- "Money" can concern "negotiable" instruments and "legal tender." I.e., property and contracts that must be accepted for the satisfaction of debts.
- One can get into legal trouble for attempting to cross a national border with more than $10k in undeclared "money," but not the same value of less fungible "property."