It's Easier to See When Users Are Inactive
Previously, a user would only be deactivated the next time they logged in to ICM.
Now ICM checks daily to see if users have been inactive long enough for them to be deactivated.
This depends on the settings you've selected under Admin > System > Settings.
If a user has been inactive according to your settings, ICM deactivates it.
This means your statistics are more accurate, which is useful if you're running reports to see if users have been inactive.