Suppression List’s function mainly is to unsubscribe a contact from all lists. Instead of doing it manually for a large number of contacts, you can import them to the Suppression List and have them unsubscribed from all lists.

When you Import or create contacts in VBOUT, their status would be Active.

If you activate the Suppression List and import or create contacts in it, their status would be Unsubscribed by default.

Even if you see the Contact’s Status Active when creating a contact in Suppression List, once you click Add Contact or you Import contacts, you will see them as Unsubscribed:

After adding this contact to the Suppression List, it will become Unsubscribed on all the previous lists he was in:

However, you can manually change the status in other lists.