Data warehouse is the place where data is transformed into information. Business softwares only store data, they are unable to forward it
because they were not designed for this purpose.
Nowadays, the demand for information and the expertise of business users requires the availability of devices that enable the exploitation of strategic information. A manager is no longer satisfied with paper-based lists extracted from his systems, but wants to use Scorecard and/or OLAP technologies, which require a separate data warehouse.
We need to mention the tendency that managers themselves would like to do ad-hoc queries and analyzes in a short time rather than waiting for them to be made by someone with IT background (device management, data location).
The data warehouse integrates all the important units of the organization, and is available to everyone on a common platform. This is the only way to ensure "one truth" in the organization.