Billing accounts allow you to add a paid subscription to a group of projects. You can create a billing account for an entire organization, a specific team, or a specific product/service within your organization. The repos in the billing account do not have to be in the same GitHub/GitLab organization. All you need to do is decide what to call it and where emails should be sent, then choose the projects that it will cover.
Billing accounts also allow you to share
dependencies.yml settings across
projects by using config variables.