I use this module to get the pagenumbers for pagination when using DBIx::Class. DBIx::Class returns a Data::Page object when using the pager() method but Data::Page can't return a segmentated output.
By simply loading this module Data::Page gets extended with a couple of methods that allow for easy implementation of pagination. The fact that it modifies the existing Data::Page module might not be the nicest thing and could lead to bugs if Data::Page would implement these methods. Still, it's a small extension so I wouldn't worry too much about it.