TL;DR

when creating multiple accounts, there are separate variables to use -- names, descriptions. But, the same display_name is used for every account.

There are places in GCP Console where the display_name is used (Enabled APIs & Services -> Bigtable API -> metrics -> traffic by credential), and the legend of the chart shows N service accounts as 'Terraform-managed service account'.

Terraform Resources

No response

Detailed design

I assume the implementation for this would be similar to var.descriptions 

  display_name  = index(var.names, each.value) >= length(var.display_names) ? var.display_name : element(var.display_name, index(var.names, each.value))

Additional information

No response