I would say Bitcoins are more a store of value, in a Similar way to gold.
However as stated:
money: is a item owned by government used in transactions (its laymens term for FIAT)
commody: a raw material used in the production of other materials/products that has a internationally recognised value and quality base.
currency: anything used as a valued item in a transaction.
bitcoins are not a commodity. you can not grind them down to make chocolate or bread. you cant melt them down to make electrical parts or jewellery. you cant cut them up to make beef steaks, or other meat products and you cant refine it to make car fuel or power generators.
so now you know that bitcoin is not "money" as that term is reserved for fiat.. its not a commodity because of it having no other practical use, so that just leave the one thing that bitcoin is useful for.. currency.
Bitcoins cannot be turned into anything else where as commodities are traditionally things that can be used to make other things. Therefore I put forward that it is simply a store of value, with the value being determined by supply and demand.