Question

Is there a reason I shouldn’t do

function bla(args){
  use(args);
}

and do this: ?

function bla(args){
  var loacalArgs = args;
  use(loacalArgs);
}

Are there places one is preferred over the other?

Answer 1

There’s no reason to do that, because args is alreayd a local variable.

function bla(args) {
   var localArgs = args;   //<-- This variable is as local as the other one
}

The only reason to refer to the same variable through another name is when you want to copy the reference/value, and modify one of them, eg:

function validate(word) {
    var originalWord = word;
    word = word.toLowerCase();
    if (word === originalWord) return 'At least one uppercase char is required!';
    // ... do something with both variables