Enrollment readers can view data at the enrollment, department, and account scopes. The data contains charges for all of the subscriptions under the scopes, including across tenants. They can also view the Azure Prepayment (previously called monetary commitment) balance associated with the enrollment.
For more details please refer to:
https://learn.microsoft.com/en-us/azure/cost-management-billing/manage/assign-roles-azure-service-principals#permissions-that-can-be-assigned-to-the-spn