Dear Anonymus Monk,
doesn't have a value of 6 because unlike an array variable a list literal doesn't evaluate to the number of elements if used in scalar context but to its last
my $scalar = qw/one two three/;
my @array = qw/one two three/;
print '$scalar is ', $scalar, "\n"; # prints
print '@array in scalar context is ', scalar @array, "\n"; # prints
for example. Perl supposes you know the length of a literally coded (i.e. hard-coded) list anyway and tries to offer you something more useful when it discovers a "Useless use of a constant in void context"...