“Scripts Dequeuer Backend” helps you dequeue WordPress backend scripts and styles from administration area. Backend scripts and styles can be easily dequeued (in controlled environment) without touching any code.
If you are running a website using WordPress, it is quite obvious that you might be using several plugins for site features and functionality. Many plugins use similar (or same) resources and it is possible that these resources are loaded multiple times in your WordPress admin. This may happen if the resource (JS/CSS) handle names are different.
For example, consider a scenario in which two or more plugins load same CSS file individually. (Say, fontawesome stylesheet). Or a case in which two or more plugins use same jQuery plugin with different handle names. Such files are loaded multiple times, causing extra load in admin area. Each time you access any admin page; these files slow down overall page load time.
Admin page load time can be improved by removing such redundant files. Removing such files not only improves page load time, but will also help in preventing issues caused by conflict of redundant files.