the gateway endpoints are free (s3 + dynamodb?), but the service endpoints are charged so that could be a reason why people don't use the service endpoints. but there doesn't seem to be a good reason for not using the service gateways. it also seems crazy that AWS charges you to connect to their own services without a public ip. also, i guess this would be less of an issue (in terms of requiring a public ip) if all of AWS services were available over ipv6. because then you would not need NAT gateways to connect to AWS services when you don't have a public ipv4 ip and I assume you are not getting these special traffic charges when connecting to the AWS services with a public ipv6 address.