Founder of gigalixir here. You're right, but I just wanted to mention that those limitations are for the free tier. Once you upgrade to the standard tier, both those limitations go away.
Founder of gigalixir here. We use GCP under the covers by default, but you can also choose to use AWS if you like. You can also choose which region you want to run in, but we only support us-east1 and us-west2, and on GCP: us-central1 and europe-west1.