Well, in all honestly, it came up on Androids due to lack of fluidity in the software optimization.

Even though Android phones have had brilliant chipsets for performance, sitting next to an iPhone, they always felt slower, and then came 90hz and 120hz, boom. They gave everyone the perception of having a faster and more fluid optimization, and that's how it became mainstream.

No denying, an iPhone with a faster display would feel even more faster than it already is, but the question is, do we really need it.

For those who'll argue about it being on the iPad Pro and not on the iPhone, well, Apple pencil. Thats what it all comes down it, people doing all sort off art work and creative stuff need that quick response, especially with the pencil being used.