The $_ example is misleading, because Perl provides a lot of extra built-in help (like implicit localization) that it doesn't provide for other such variables. (I can easily imagine perfectly well-behaved modules that make heavy use of $_ without ever using a single explicit localization of $_.) Without this extra help I think the use of $_, at least in modules, would become much less attractive. An even with all the extra help, the use of $_ is still fraught with trouble.