For a society, government and associated financial system money raised through taxation may be viewed as a commodity.
Tax revenues may rise and fall from year to year, there are some taxes which remain stable for example corporate tax returns may fall whilst individual tax returns remain stable.
Aristotle first defined the characteristics of a commodity that can be used as money as (1) divisibility, (2) durability, (3) portability and (4) scarcity, i.e., rare and valuable.. tax revenue / payments meet these requirements..
Robustness of tax
Individuals annual tax returns are a known fixed number
Government tax revenue is a known number