Screen protectors are a personal choice for people. I personally use one on my iPhone even though the new iPhones have a great screen on them. I still think that it is necessary to use one, but in some cases, people don't like the way they look and don't want to invest in a screen protector.
I still worry about my screen getting damaged and broken if it is dropped or knocked off a table. I don't want to risk the chance of my screen breaking so I protect my screen and phone with the screen protector and also with an anti-shock case. This gives me peace of mind and ensures me that I have done what I can to protect my investment. You will be the one who decides if you want to invest in the screen protector for your phone. If you trust the new screen on the phone, then I'd say no you don't need it. But if you are afraid that it will break, then yes you need it.