I thought about this too. You're correct that the /g modifier is kind of pointless by itself, but combined with the /m modifier, you get improved functionality (for some definitions of 'improved'):

use strict;
use warnings;

my $string = "   now is the \ntime for all     \n       good men to co
+me    \n          to the aid\n";



$string =~ s/^\s+//mg;
$string =~ s/\s+$//mg;

print $string, "\n";
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