Sim Racing, in short for simulation racing, is a collective term for racing games software to attempt accurately simulate car racing virtually.
The simulation software along with sim racing hardware simulates all possible feedback that a real car provides such as tyre wear, fuel usage, aerodynamics, grip and suspension movement.
In order to get into sim racing especially becoming a competitive driver, you must understand various aspects of how the car handles while on track.
This includes maintaining the control of the car as it loses traction in such velocity and using the correct driving line to maintain speed to make those fast lap times which is not easy both virtually especially in the real world.