Yup! Have tried this in 5.10.1 and now see the difference.

use strict;
use warnings;
use 5.010;

my @arr = (2, 5 , "aaa");

say "\@arr ~~ 5 matches" if @arr ~~ 5;
say "5 ~~ \@arr matches" if 5 ~~ @arr;
say "\@arr ~~ 3 matches" if @arr ~~ 3;
__END__
5 ~~ @arr matches
[download]

But after reading "Smart matching in detail" from perlsyn I have the impression that @arr ~~ 3 expression falls under

    Any  Num   numeric equality  $a == $b
[download]

See the fourth (last) part of Re: smart match operator should be smarter!