With a emulator it's easier to use save states and splice different parts of the run together, or to otherwise cheat. Given that Billy Mitchell has stated that

With a emulator it's easier to use save states and splice different parts of the run together, or to otherwise cheat. Given that Billy Mitchell has stated that he never used a emulator but the footage contradicts that, a lot of people believe he may be lying about using an emulator to hide the fact that he was cheating using an emulator.