Its preference, most people say play with what you find comfortable, I was not using Cookiezies tapping style.
But a long time ago when I was 160k rank I was playing a lot of various artist long stream practice maps and have developed arthritis. Because of that, i decided to change my tapping style.
I saw Cookiezi supports his index finger with the thumb. So I was like why not try it, I tried it and had less stress on my wrist.
However, streaming with the thumb that supports index finger was awful. So I didn't give up, I kept playing that style, I kept failing, and failing until one day I was able to hit some cool streams.
Then because of that, i proceeded to stream all day and fuck my wrist. It was burning but not painful. This means my streaming speed increased overtime etc... Then I was like my pen grip is kinda too simple, why not make it complex.
I looked at Cookiezi pen grip and it was "retarded" as fuck. However, I want to become like Cookiezi, so I proceeded to copy his style. It took me 1-2 days to have its good position and my thumb tip was hurting because Cookiezi holds it with his tip of the thumb.
Now I am just getting used to the aim, also his pinky touches the tablet I think it helps a lot of the aim.
Anyway, I am gonna update this thread if I will get any improvement.