When I had my black Nissan 350Z back in 2003, I was using "ZAINO" and it was very common for Zaino users to apply a coat each time they washed the car to build up many coats of Zaino.
Well, when I had 11 coats built up I was backing out of a covered parking spot and cut the wheel to soon and my front fender hit the rusty and rough square aluminum pole.
Made a fist sized dent, but.....the paint was NOT scratched!
The 11 coats of Zaino just smudged!
So I did a quick "spot" removal and reapplication and was good to go.
I have been a believer in that stuff since.
Now obsiously, if someone hits your car with their door or you get hit by a rock its probably not going to protect you.
But for those annoying small particles that you hear pinging your car as you drive it might work.
The 350Z was infamous for having a crap plastic front fascia that was resistant to any kind of polish or wax.
So bad in fact, most guys bought 1 or 2 extra front pieces...no lie!
Or just kept having it repainted.
But in all, I think Zaino does indeed help more so than others based on my pole hitting experience.