Concise. Documented, standard and configurable handling of existing variables (may be used for default values etc.) via EXTR_OVERWRITE, EXTR_SKIP, etc. Documented, standard behavior of compact() in regard to missing variables. No manual associating of foo with $foo -- less places for mundane errors.

Oh, and there's even that EXTR_IF_EXISTS -- so my silly idea to sanitize with array_intersect_keys() was totally unneeded. Make it

  $foo = 123;
  $bar = getSomeBar();
  $coot = 'boot';
  myFunc(compact('foo', 'bar', 'coot'));

  function myFunc($kwargs) {
    $foo = 1;
    $bar = 'xyz';
    extract($kwargs, EXTR_IF_EXISTS); /* sanitization: $coot will NOT get extracted 
        because the function doesn't expect / support that argument */
    ...
  }