These days, with food distribution the king, you can get anything pretty much anywhere, so BP availability is no criterion. Furthermore, what is clear from this thread is that sausages/salamis similar to BP are also native to other countries like Spain.

In Greece we wouldn't bugger a perfectly good all-meat-and-fat-and-salt-and-pepper-and-whatever-granny-found-at-the bottom-of-her-shoe sausage by adding blood. No need. The ancient Spartans had another use for it instead: Melas Zomos, literally "Black Broth", a soup that the warriors would fortify themselves with before the went to battle. Unfortunately the recipe has been lost through the centuries, but we do know that it included sheep's blood.