$/ can also be re-set by the script to some other value (other than \n). If the script sets $/ to "End of Record", and you use $/ in place of \n... well, you know what it's going to print.

I don't mind seeing $/ here and there in one-off scripts, but can't imagine why you would use it to represent \n in a script that's going to be around awhile. It's definately not something you would read in perlstyle.