benefits of an Array Column?

I was reading the o'reilly practical PostgreSQL book and came across
the chapter that mentioned the Array Column.

I fail to see the scenarios where this would be an useful feature.  How
is this better than linking to another table that could serve the same
purpose?

For instance, the example used in the book metions the "favorite books
of employees" by using a column for employee name and array column of
favorite book titles for that employee.

I could also approach this by having an employee master table and book
titles master table then creating a third table between these two
tables that would have rows that matched up employees with their
favorite titles.


Jared