Kulea automatically unsubscribes users if they click the unsubscribe link in an email campaign. Unsubscribed users will not receive any email communication from Kulea and are removed from your mailing lists. They will however remain included in personas, generate lead scores as they navigate your website and will be included in your opportunities.
An archived user however is removed from all activity, including opportunities, personas and email marketing. They will not generate a lead score if they navigate your website.
It is best practice in CRM to never to delete a user but to archive them. Why? If you delete a user it is permanent and you have no access to their historical information should they decide to return.