Hi, if you are worried about the limit on emails per hours, the BCC does not solve, usually, the problem. An email with 2 address produces on the first mail server two distinct deliveries and so it counts for two.
More, sending an email in with BCC does not permit to track the user activity on that email, add the user-specific unsubscription link and so on.
Hence Newsletter cannot work with BCC.
Stefano.