See also 'our' is not 'my' (it's linked from the tutorials, under variables). In short, the only advantage is if you've got a lexical variable and a global variable with the same name. my declares a variable and its scope. our declares the scope in which a name refers to a global variable. A subsequent my would override a previous our, and a subsequent our would override a previous my.

Of course, if you override a my at the same level, you've effectively pushed it out of scope. You can't reach that variable anymore. I don't know whether Perl itself considers it an end of scope, though.

If, instead of replacing it with our, use vars had been upgraded to a real, scoping pragma, then there could have been a no vars to declare the end of global scope, and you'd get your lexical back.