I'm quite new to this so I'm trying to figure out the reason for ActiveDirectory existing in the first place.
The main benefit of active directory is centralized management. It allows you to do things like
- Centralized account and password management - users have accounts that work on all machines in the domain, when changes are made they work throughout the whole organisation. On a standard Windows Work group, to reset a password, you would need to do this on every machine where an account for this user existed. It also means accounts can be disabled centrally if a user leaves the organisation.
- Centralized computer management
- Group policy - Apply User and Machine policy's to control what user can and can't do.
- Rolling out software to machines on the domain
- Provides a central directory of all users in an organisation, including contact information if required
These are some of the very basic benefits of AD. There is much more it can do. If you want to find out more, I suggest you take a look at this page.