The scope for Build Arguments can be global at the account level or specific to a single application. If your build arguments are used on every application then it's best to keep them in the Account Settings under the Builds tab, but if you have secret environment variables that are relevant to a single application only, then you will want to add them in the Application Settings under Advanced Settings so they won't be exposed on other containers. The process is the same whether you add them globally at the account level or at the app scope, with the only difference being which settings you navigate to in Release.