I am interested in the thought processes behind setting up separate AWS accounts "for GDPR compliance" as opposed to having one AWS account and running multi re

I am interested in the thought processes behind setting up separate AWS accounts "for GDPR compliance" as opposed to having one AWS account and running multi regions (via VPC etc.) under that account? Is it because teams in different locations (US, EU etc.) can run semi-independently? How do you manage shared resources (e.g. S3 or RDS SQL servers) that need to be accessed from multiple regions, yet still maintain GDPR compliance?