What is the importance of mapping Customer Series Credit master?

Suggestions:
The customer-division related specific information is to be stored in this master. This master specifies for each customer, the division(s)(series) that are applicable. The Sales & Distribution module checks for the customer division entry in this master and if the record is not found the products of that division is not allowed to be sold to the customer.
For mapping below values are to be given:
The system displays the Item series applicable for the customer series and displays the site applicable for the customer.
Users should enter the Customer applicable for the customer series credit. It can be selected from the pophelp for Customer master.
Users have to enter the Credit term applicable for the customer series. It can be selected from the pophelp for Credit term master.
Users can enter the maximum credit to be given to the customer for the specified series, beyond which the credit check fails.
For the customers to be black listed, Black Listed values should be selected from the drop down values. It indicates Whether the customer is black listed or not on the ground of non payment. Y-yes, N-no. If the customer is black listed, the system will not accept any order for the customer. Users need to enter the reason code for Black Listing and date from which the customer is black listed. Orders cannot be accepted from the customer from the specified date .
Hold Shipment can also be done for a specific customer series combination. Its value should be selected from the drop down values. It indicates that If Yes is selected then orders can be accepted from the customer but dispatch will not be allowed. If No then orders can be accepted and dispatch be allowed.