That's a NAT gateway, but if you're pulling data for analysis from S3 buckets you don't have those limitations.

Let's say they decide to recalculate or test a algorithm: they do parallel data loading from the bucket(s), and they're pulling from the wrong endpoint or region, and off they go.

And maybe they're sending data back, so they double the transfer price. RDS Egress. EC2 Egress. Better keep good track of your cross region data!