I'm speaking, of course, of when it's best fit to use a variable/subroutine instead of some other technique.

Accessing the global handle through a subroutine makes it much harder to accidentally clobber it.

True. I didn't think of that, especially since he uses it as foo()->bar, and it's hard to modify it that way. I don't think there's a high risk of accidently modifying this particular variable, but I see your objection.

(Further, it makes clear to anyone reading your code that $handle has a well-defined value that doesn't change, which is kind of nice for maintenance programmers.)

By convention you name those variables in upper-case, so in this case it would be $HANDLE instead. There should be no larger question marks regarding that issue.

I think that the small risk of clobbering the variable is out-matched by the warning feature of variables. It helps to keep code clean, and that is something maintainers also appreciate. I hate seeing unused subs/variables just because the author was too afraid/paranoid to remove them.

Cheers,
-Anomo