Active Directory is just a centralized authentication and object database... it isn't much more than that.
The good stuff (in this aspect), is Group Policy. The main part of Group Policy, administrative templates, is (basically) just an easy categorized and searchable GUI way of centrally controlling the registry of multiple Windows clients.
There are a ton of other Group Policy extensions as well, like all those included in Group Policy Preferences for example. So for fine-tuning and centrally controlling all settings and such of Windows machines (clients and servers), and other objects, Group Policy is really a very convenient way of doing it.
I would think Salt compares to SCCM (it is just a configuration manager after all).
I'd use Salt in place of Group Policy and other configuration managers. But if you already have AD/Group Policy and System Center, there's really no need, unless you also have a lot of Linux (or other) based OSs.