That aliasing command relies on typeglobs to work.

Therefore it will only work with global variables. (ie you must localize with local, not my.) I stay away from that except when it really doesn't make sense not to. :-)

The mostly widely used form of that kind of aliasing in modern Perl is for exporting symbols using Exporter.

FWIW one goal for Perl 6 is to kill typeglobs entirely. The functionality should be available, but by a different mechanism...