> * They are willing to use euros as a medium of exchange, but only because they know they can exchange them for (to them) real currency.*
Any person or business is only willing to use a currency as a medium of exchange because they know they can exchange them for other goods. "Currency" and "medium of exchange" aren't mutually exclusive, the former is a special form of the latter that is recognized widely (and in modern times, usually has no intrinsic value).
> * To be money you have to be willing to save it. If all you do is use it as an intermediate it's not money - yet.*
That's an insane definition for "money." You would claim that the fast food wages of a teenager who always spends it immediately is not money.
> You would claim that the fast food wages of a teenager who always spends it immediately is not money.
Just because he doesn't save it doesn't mean he's wouldn't be willing to if he had a lot of it. He isn't spending it because he thinks it doesn't keep value, he's spending it because he wants to buy things.
Any person or business is only willing to use a currency as a medium of exchange because they know they can exchange them for other goods. "Currency" and "medium of exchange" aren't mutually exclusive, the former is a special form of the latter that is recognized widely (and in modern times, usually has no intrinsic value).
> * To be money you have to be willing to save it. If all you do is use it as an intermediate it's not money - yet.*
That's an insane definition for "money." You would claim that the fast food wages of a teenager who always spends it immediately is not money.