No, bartering with it doesn't make it a currency.
However what money is (the abstract concept) and what a currency is (the actual thing you use) is subjective. Art could be used as money and a currency, just as well as sea shells or cigarettes can.
The key is it being used as a medium of exchange, not as something you get for its own gain. So trading art, for the sole purpose to trade it for something else, is using it as a currency.