FWIW, note that in the second example here, the outer for-loop is not needed:

c:\@Work\Perl\monks>perl -wMstrict -le
"my @re_subs = (
     sub { s/(?:this|or|that)/bob/gsi  for @_ },
     sub { s/(?:One|Two|Three)/Four/gs for @_ },
 );
 ;;
 my @strings = ('tHiS one or ThAt other', 'One two Three');
 printf qq{'$_'  } for @strings;  print '';
 ;;
 $_->(@strings) for @re_subs;
 printf qq{'$_'  } for @strings;  print '';
"
'tHiS one or ThAt other'  'One two Three'
'bob one bob bob other'  'Four two Four'
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That's because of aliasing through the  @_ function argument array. Actually, the work of the outer for-loop is just being moved to the for-loop within each anonymous subroutine, which is now given something to loop over whereas before it was just being used for topicalization.