... which isn't a symbolic reference??

Yes, but it's not any safer than symbolic reference. Given that symbolic references are easier to use, you might as well use those instead of messing with %::.

Compare

my $r = do {
   no strict 'refs';
   \${"${pkg}::$var"}
};
[download]

with

my $r = do {
   $pkg_ref = $r->{$_."::"} for split(/::/, $pkg);
   \($pkg_ref->{$var})
};
[download]