Having a website that allows users to register will allow you to distinguish between casual visitors and other visitors who provide added value (customers, suppliers, employees, ...)

Therefore, this type lets you create web pages that will only be visible to users you choose. may publish them

•  internal documents
•  manuals for products or services of your company
• price catalogs for wholesalers
• ....

Surely you will think of many more utilities for an area of ​​exclusive access to registered users in which to publish content from ocn restricted tranquility.