I mean that flight instruments like VOR and other gyro and pitot-static instruments will behave more smoothly and naturally to the way they built
In the simulator, when I turn the OBS knob, the CDI needle and the TO / FROM flag, jumps from place to place.
In reality, everything works more slowly and smoothly and it take time to the needle to stabilize because these are works radio waves:
The same goes for pitot-static devices, these are changes in air pressure, so in many cases the reading will not be completely accurate - in reality, if I pull the yoke towards me roughly, I will first see a descend trend in VSI and only then a climb trend
There are many more examples but the intention is to make the experience as similar as possible to the behavior of devices in a real plane to allow instrument rating students to use this simulator as a training tool similar to XPLANE and other professional simulators.