I don't think bitcoins are an economy by itself. If you say economy it is something that is produced and consumed by the people.
In bitcoins there is only a medium of exchange, nothing else. There is no economy to speak of here. The only thing bitcoins would
be in an economy is a way to pay for stuff, but it can't produce stuff, nothing goes around.
There is an ongoing economy in bitcoin right now most of the money is used to buy virtual goods in the form of other crypto, but there are people using their bitcoin to buy physical products but this aspect is not going very strong since the fees are not the best for this kind of activity.