Two use cases come to mind. Some of my users are spouses and only want one account on their newsletters. So there would be a main for one spouse and the CC would go to the other spouse. Second is some of my users like to receive their newsletter via text/SMS. I use an Email to SMS conversion so the CC would go out as an email to their text As well as to their main email.
Are used the plug-in extensively in version five for my users. I’m trying to upgrade to the new version and this is a show stopper for me.
Maybe the plug-in for cc to a subscriber from version five could be modified.