In general references are useful for creating nested data structures such as an Array of Arrays, Hash of Arrays, Array of Hashes etc. Check out perldsc for lots of examples and further explanation. The first several chapters of Mastering Algorithms with Perl also provide good recipes using references.

• UPDATE: The update/addition to dbs' original question (entire script from 2004) makes it much clearer that it's specifically about the benefits of code references and not references in gerneral. Please skip down for some more specific responses. :)