From Wikipedia: > In economics, a commodity is an economic good, usually a resource, that specifically has full or substantial fungibility: that is, the market

From Wikipedia: > In economics, a commodity is an economic good, usually a resource, that specifically has full or substantial fungibility: that is, the market treats instances of the good as equivalent or nearly so with no regard to who produced them. I am pretty sure you can get BTC from any exchange and sell it on any other exchange. Whereas, with stocks, you generally cannot as a retail investor. That is, I suppose, what makes crypto a commodity at its core.