Difference between .info files hook_menu() file key?
I'm sorry you do not understand my question, however, I believe the question was pretty straightforward. After discovering some interesting articles I think worked out my confusion.

The files[] entry in the module .info file is not used for "including" php files. It is meant only to auto load your classes and interfaces for your application (if you're writing your module using object oriented methodologies). It could be thought of as the "import" statement in Java. 

The following articles go more into detail about PSR-0 standard and auto loading in php.
previousnext.com.au/blog/drupal-8-now-psr-0-code-drupal-7/
riceball.com/d/book/export/html/1200

That being said, the purpose of the file key inside the hook_menu() $item[] is to specify where the file containing the page_callback function exists. If your page_callback function is defined inside a class (statically), then you do not have to provide the file and filepath keys. The callback would look something like this,
    'page_callback' => array('MyClass::myfunction');

For more information on OO Page callbacks in Drupal 7, read the following article.
previousnext.com.au/blog/object-oriented-page-callbacks-drupal-7

If your page_callback is not inside a class, but just inside a file then you'll need to provide the file and filepath keys so that Drupal can include this file when your page is created.