ACP is intended to make it simpler to maintain a Joomla site. It's designed to address two common problems:
2. Multiple articles that are created by copying an original template, creating duplicated content.
The first problem makes it nearly impossible for a site developer to hand over content management to an end user. One careless edit and the article fails to display correctly. This is both frustrating for the user and it defeats the purpose of using a content management system.
The second problem makes it more difficult to maintain a site. Everything is fine as long as the template doesn't change, but if it does, there are multiple copies that need to be updated manually.