I think "pixel perfect" refers to matching a designer's visual design. iOS developers should have been using the layout constraints for most of the UI - if they

I think "pixel perfect" refers to matching a designer's visual design. iOS developers should have been using the layout constraints for most of the UI - if they have hardcoded values, then that is bad programming. For apps that use a lot of UI graphics in the form of images, yes they have work to do. But the same would be true on Android.