Recently I helped facilitate a migration from public ALBs to private NLBs for a client. So I see the use case for private ALBs, as for private APIGateways I could see a large company creating an internal APIGateway to route requests inside of their VPC. Well now you can assign your own private domain name to that API Gateway if you want. Enjoy: https://aws.amazon.com/blogs/compute/implementing-custom-domain-names-for-private-endpoints-with-amazon-api-gateway/