> Especially, not exclusively.

It's like the difference between "car" and "vehicle". Not all vehicles are cars. Not all money is currency. The boundary is not precise. Is an SUV a car? Maybe. Is a semi truck a car? Definitely not. But it's still a vehicle.

Is a dollar bill currency? Yes. Is the balance in your checking account currency? Maybe. Is a check currency? Definitely not. But it's still money.

> Also, are cryptocurrencies not currencies?

No. It's arguable whether or not they are money. The U.S. government treats them like a commodity for tax purposes.