2 Decreased Keyboard Responsiveness
Apple designs its products very carefully, and because of that, the hardware and software in an iPhone are specifically optimized in a certain way. Getting your screen replaced by someone other than Apple can throw all of that off.
Using a non-Apple screen has been known to affect the overall responsiveness of your display — from typing on a keyboard or using 3D Touch. Some users who got a third-party repair even report “dead zones” where touches aren’t registered.