Not speciality. They were used by any high-end monitor. There were junk panels, mid-range panels, and high-end panels. IPS panels are generally found in the mid to high range. I am speaking from a photographer's point of view where viewing angle and colour calibration are important. For the less serious gaming segment, speed of the panel is more important. I mean, does it really matter if gore in a game is 2 points less colour accurate.
Generalize much? Apple's monitor's are good mid-range monitor, currently. Not the best, and not the worst. There is some talk about the glossy panels being hard for photographers. But they are supposedly pretty good for watching a movie. The colours are supposedly stunning.
Let's see.... Apple makes monitors to fit Apple's computers. Do they connect to Apple's computers? Oh, my look at that .... they do!!

Why would someone then want to pay for connectors they don't need?
Can't compare those. The LED is an important part of the monitor, and not just for energy consumption. The non-LED backlights tend to fade and change colour over time. Again, gamers don't care - their needs are not as strict as anyone doing colour correct work.
One of the big problems I've read about the Dell monitors is that the model and manufacturer of the panel changes from month to month, depending on which factory can meet the price points. So, their consumer stuff may be nice individually - you can't count on any consistency from one monitor to the next - despite being sold as the same model.