Actually, things can be out of scope regarding VAT. VAT is charged on the delivery of goods and services. So if transferring Bitcoins is neither a delivery of a good nor a service, Bitcoin is out of scope.
Yes and "services" if basically defined by "everything that can be billed and does not end with the delivery of goods".
It is more subtle than that. The VAT directive defines "Supply of services shall mean any transaction which does not constitute a supply of goods". However, "transaction" is earlier defined as supply of a good or service (article 2). Thus, all the directive says in the end is that "transactions" = "supply of goods or services", without defining more closely what a service is.
It boils down to the question what the service is, that a Bitcoin exchange provides. The reasonable interpretation is that the service an exchange provides just consists of the matching of buyers and sellers. Thus, VAT should only apply to that service, and not the exchanged amounts. Similarily, ebay only charges VAT on its fees, and not the value of the traded goods.
Now, what makes this all so confusing, is that there are exemptions for financial services such as running an exchange, which raises the seperate question of whether VAT applies to the fees or not.