The best example I can think of, is when you generate a huge array to be returned from a sub. If you return the array, a huge copy is made and returned. If you return the array ref, you just return the memory location of the first array element. It is far more efficient just to return where the array is loacted, rather than the array itself.

my $aref = get_values();

sub get_values{
my @array = (1..5000000);
return \@array;
}
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Of course for small arrays, it really dosn't matter.

Another place you will see references used often is in objects. You don't want to pass around copies of objects, so you pass their memory location (reference). Inside the object, the object refers to itelf as $self, because it dosn't care where it is located.