The merchant integrates technically with the gateway rather than separately with each PSP already supported by that gateway.
The gateway manages its PSP integrations, while the merchant maintains the required commercial, onboarding and compliance relationships with each PSP.
Compared with orchestration, a gateway generally provides a more fundamental payment-processing layer and may offer less advanced routing, rules, cascading/failover and automation.
Availability is subject to jurisdiction, provider underwriting, compliance review and partner acceptance.