...it makes much more sense for Perl to deliver this kind of trivial but essential stuffs as part of the language itself...
I couldn't agree more. But suppose I would find the courage to go into the Perl innards so that this would be possible in 5.10. Wouldn't it then be nice to be able to use that idiom in older versions of Perl as well?
And vice versa, the "public acceptance" of this module would be a good indication of whether it would make sense to put such a feature in the core Perl itself.