If you have ever developed large scale enterprise level WordPress plugins you probably have encountered the situation were you have tons of php class files. But you don't need all of them all the time at run-time. To make sure that all these files are loaded you have write tons of lines of code to get all these files loaded when needed.
Thanks to the WP Autoloader you can forget about writing any line of code to include your class files. You have to take care about valid files hierarchy and thats all. Just make take care that your namespaces and files hierarchy is synchronised, put all them into the ./lib folder and WP Autoloader loads all of these classes automatically only when needed!
WP Autoloader can help to increase the performance of your WP plugins up to 99%! Tested! True!