The main difference between Mod Apk and Original Apk is that there are no restrictions associated with them.
Some users might not want to spend money on in-app purchases to enjoy the full version of an App, that's where Mod Apk's come into play. No need to worry about payments now and then.
Another significant difference between regular apps and modded apps is that you can modify features according to your choice without having any limitations imposed on them by the developer.