Many people wonder what the differences are between the FAA-certified version of X-Plane and the standard home version. The short answer is: not many! However, what differences do exist may be very important for your flight training.
First and foremost, the FAA-certified version checks the simulator’s frame rate and hardware to make sure that both are okay before allowing flight, something that is not done in the desktop version. You will need to mark the appropriate hardware axes as required in settings, and thereafter X-Plane will require these axes for use.
A professional key also unlocks the ability to use cylindrical and spherical projection (as found in large simulators), and the ability to drive Garmin Real Simulator Units.
To summarize, the certified version of X-Plane includes all the scenery and capabilities of the home use simulator, but includes additional hardware and frame rate checks, as well as cylindrical and spherical projection capabilities.