The mission of the Data Warehouse
The purpose of a data warehouse is to extract, clean, conform and then deliver the data to end users.
It can be thought of as a magazine publisher, there is tons of work that goes on in the background the readers never see, however, it the readers that the success of the magazine depends on.
So too does a data warehouse rely on the end users to justify its success.
References
The Data Warehouse ETL Toolkit pg 22, 23