First of all this app is of no use and it never works. I have tried it many times on my secondary phone and the results were rubbish.
And why do you need to root your phone because your phone is capable of handling it itself. The only care you need to take is of it’s outside handling you don’t need to handle it’s software.
I have seen many people and students of small age who just want to root their phones for no reason. Keep in mind you will destroy your phone instead learn something good using your phone.
And the ads are of extreme level so please don’t waste your time.