I mean sure. Anything someone is using like currency can be called currency. But we’re talking practical terms here. Things we “collectively agree to value.” My WoW gold might be useful for buying potions, but it’s not generally accepted anywhere outside that narrow context. The fewer people who are willing to accept the currency, the less useful, and arguably less “real” it becomes, in so far as currency is defined by its value to others. I could print “me bucks” that I value at $1B USD, but that doesn’t mean much if nobody will give me a sandwich for it.