The primary reason to use views is to simplify end user access to the database. Views provide a constant vantage point from which to examine and manipulate the database. Their perspective is altered neither by adding or nor by dropping columns from its component base tables unless those columns are part of the view definition.
From an administrative perspective, views are useful for providing an easily maintained level of security and authorization. For example, users in a Human Resources department can access tables containing sensitive payroll information without being able to see salary and bonus columns. Views also provide administrators with an ability to control read and update privileges on the database with little effort.