But the value of dollar is halved every decade through supply inflation. That's why the price of houses doubles every decade while their value is relatively stable.
Do you mean medium of exchange? I think it's difficult to make the claim that the USD is a good store of value.
Money has the property of medium of exchange, yes. It's also a store of value, and a unit of accounting. I took econ 101.
Flowers are also a store-of-value, but like the dollar, not a very good one.