The benefit this provides is the reduction of files the browser has to download prior to displaying your web page.
The thing is, most of those files are tiny. They only have a few lines of code. If you find you have such files they should likely be inlined into your HTML to save the external file calls.
How to inline JS
Basically you just copy the contents of your external JS file and paste them between script tags into your HTML.
It looks like this:
What does this do?
Putting your JS into your HTML will save the web browser a round trip to the server, since you are no longer asking for a separate external file for the browser to load to see and execute your JS.