> And half the time it doesn’t work because the hash is actually a ref

Perl still supports both „copy by value“ and „copy by reference“. For example:

  my @copy = @original;
  my %hash_copy = %orig_hash;
  my @processed = foo_func(@copy);
  my $ref = \@copy;
  bar_func($ref); # modifies @copy in place

That’s why it uses these sigils to distinguish between references being scalar values (“$”) and actual lists/dictionaries (“@“ and “%”). Since Perl is also dynamically typed if it weren’t for the sigils, it would be quite confusing when reading “array[i] =“ somewhere not knowing whether it modifies an array created remotely or locally. Sigils communicate that because it reads “$array[$i] =“ for a local array or “$$array[$i]” for a remote one.

In other languages like JavaScript or Python everything is basically a reference and, hence, you don’t quite need sigils there. However, on the flip side, you need to be more careful and constantly remind yourself of the fact you are dealing with references and not to accidentally modify the objects you get passed into your function.