There is more than one reason to do this. Sometimes makes common join queries easy as one can just query a table name instead of doing all the joins.
Another reason is to limit the data to different users. So for instance:
Table1: Colums - USER_ID;USERNAME;SSN
Admin users can have privs on the actual table, but users that you don't want to have access to say the SSN, you create a view as
CREATE VIEW USERNAMES AS SELECT user_id, username FROM Table1;
Then give them privs to access the view and not the table.