New given/when return, why is that?

Allows DRYer code. So something like this:

    say do {
        if    ($grade eq 'A') { 'Well done!' }
        elsif ($grade eq 'B') { 'Try harder!' }
        elsif ($grade eq 'C') { 'You need help!!!' }
        else                  { 'You are just making it up!' }
    };

Could now be written this way:

    say do {
        given ($grade) {
            'Well done!'        when 'A';
            'Try harder!'       when 'B';
            'You need help!!!'  when 'C';
            default { 'You are just making it up!' }
        }
    };