Thank you for reaching out to the Community! We completely understand why you would want to permanently delete your email campaigns. At the moment, we do not have a way to permanently delete them just in case you need the reporting information later. We can add you to the list of people who want this feature as well. Thank you!
It is a good idea for campaigns to go into a holding pattern, sort of like a recycle bin just in case. However, there are situations in which you would want to permanently delete information. Perhaps there is confidential info in a survey that you have exported then want to delete. Currently there is no way to have confidential info if a team works in a CC account. There needs to be a permanent option for removing information.