A well architected infrastructure includes capabilities and services that can be exploited and reused by multiple applications. Security checking is an interesting need, and you must determine where it is needed and how it is deployed. Often, security is not planned for up front and gets added later. However, when multiple applications are being developed and deployed concurrently, the organization may find that it has just reinvented security solutions for different applications. While the application-specific solutions work, they do not have common interfaces for enforcement, and the end user may get stuck needing to know different IDs and passwords.
Good security is planned for up front, and implemented using common security services.
Having common security services, or a reusable security infrastructure, should be of interest to all groups involved in the applications. End users should reap the benefit of the underlying security infrastructure as the applications deployed all can understand who the user is regardless of which application the end user executes. This can be classified as end user single sign-on. This should translate to faster application development since the team can focus on application development instead of security development. As people come and go, and as the security policy or needs change, there is ongoing administration needed to accommodate the changes.