hmm, re behaviour in list context, I'm getting different results from you:

use strict;
use warnings;
use Data::Dumper;
use feature qw/say/;

my @a1 = 'aaa' ~~ /./g;
my @a2 = 'aaa' =~ /./g;
say Data::Dumper->Dump([\@a1, \@a2], [qw/smart_match re_match/]);
[download]

gives me

$smart_match = [
                 1
               ];
$re_match = [
              'a',
              'a',
              'a'
            ];
[download]

with v5.10.0 built for i686-linux