I dislike "cute" uses of fat arrow, because the following code is broken:
in reply to Re^2: Use of the m/.../g idiom in list context (formatting MAC addresses) (use of fat commas)
in thread Use of the m/.../g idiom in list context (formatting MAC addresses)
Yes, smart people know that fat arrow autoquotes the left argument. But why should you require your code to be maintained by smart people?
use constant COMMA => ',';
my $result = join COMMA => @list;
# should be: my $result = join COMMA, @list;
Be kind to your maintenance programmer. Don't use fat arrow except when you want the quoting feature.