If you use your Leads/Prospects section to create lists for sending email to prospects, you know that there are times that the recipient will "unsubscribe". When unsubscribes happen, you must take steps to ensure that recipient will never be contacted again by your organization.
Argenta offers two ways to handle this type of situation. You can flag leads/prospects as "DO NOT CONTACT", which will remove the leads from the list (unless you specifically filter for them by that status). This way when you're creating mailing lists, these leads will not be included.
There is also another way to ensure these leads/prospects never get added to another mail list. You can kill them. Killing a lead can be beneficial because it eliminates unneeded records from your subscription, while creating a way to keep "dead leads" off of any mail lists.
These "dead leads" are saved for two reasons. First, leads in the dead leads list are prevented from being added back into Argenta without flagging you that their status is "Do Not Contact". This ensures that leads are not solicited unlawfully by your organization. The second reason for maintaining this dead leads list is so you can add the leads back into the lead list if necessary. Argenta uses the dead lead list to maintain their most important information.