No confusion there, but with the power of call I can invoke the Array.join method on a plain old object.
The main point here is that yes there are methods that are associated with a certain kind of Object that is made with a certain kind of constructor function. However if any object just happens to have values that a method uses, call can be used to invoke a method on any object regardless if it is an instance of the constructor that it is associated with or not. A real simple way of thinking about it, is that Call can be used to free methods from there prototype.
So call is a property of the Function prototype, which means it is a method that works with any function, including methods that are part of the prototype of any kind of Object like Date, and Array. Call works by using the call method on any function that I want to use with a certain object in which it might work by passing that object as the first argument. This Object will become the value of the this keyword when it comes to the body of the code that defines the method I am using. Any additional arguments are just the arguments that normally get passed to the method that I am using with call like normal.
Apply works the same way as call, but you pass an array of arguments.
Bind will return a new method that can be used with the given object. It Works just like call, and apply, but will give you a new function that can be assigned to a variable, and called all over the place.
Yes call, apply, and bind are pretty helpful. They allow for me to break methods from there prototypes and use those methods with any object.