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.
Maybe what op wanna say here is instead of bitcoin,its the cryptocurrency is the economy..this imore accurate to mean because all crypto has their own market and services offered thats why it will considered as economy