Until recently, the settings included the option to delete all messages in the mailbox on the server. In my opinion, this was very useful when using a profile on multiple devices, as the messages weren’t deleted from the server immediately after being downloaded. Now, if the mailbox is full, the messages can no longer be manually deleted from the server.
Furthermore, when using test profiles, it made sense to delete all messages from the mailbox before testing. Unfortunately, using a mail client for this purpose is no longer possible, as the password is not displayed in the advanced settings.