Here my top reasons why you should root your device:

1.) If you are rooted, you are able to patch your device to ignore significations.

2.) You will never have the problem, that you have to remove the original game before you can install a MOD. You can install MOD over playstoreversion and playstoreversion over MOD to play legit again.

3.) You will never have the problem to loose your savegames.

4.) You can always login with Google+.

5.) You can login with facebook without removing the Facebook-App.

6.) You will be able to install ALL MODs on this planet.

7.) You have millions of possibilities.

8.) You will never need to pay for a premium version of an App.