Getting a distinct list of node names

Hi all,

Back in december 2003 G. Ken Holman posted an excellent solution on this
topic. However I got a question to his solution.

His solution was the following:
  http://www.biglist.com/lists/xsl-list/archives/200312/msg00649.html

Now my question is, what is the generate-id for? When I write
  .=$childnodes[name(.)=name(current())][1]
this works just as fine. Is it advisable not to use comparison of objects,
but rather compare strings or so?

Yours sincerely,
Paul