Scope
Archive unused gateways
Stop using the gateway for new signups but existing customers should continue
If I archive a payment gateway can existing customer do card transactions associated with that gateway
Archiving the gateway:
This means that customers who are already using this gateway, will continue to do so, but no new customers will be able to make use of this gateway.
Removing the gateway:
This means that no customers (old or new) will be able to make use of this gateway any longer.