There are two use cases here.
1. There are multiple main contacts for a company, so I want to send the sequence to all of them, and if any one of them replies, I want the sequence to end.
2. My coworker wants to be bcc’d on sequences where users are invited to book a meeting with her. It would help her and I keep track of meetings that are booked through sequences and she wants to be able to get the emails. The solution would be to allow me to bcc her to individual email sequences, or subscribe here to the Sequence anytime it is sent out in the sequence settings