On a physical PS3, cheating typically required third-party hardware like an Action Replay or GameShark, or complex save file modifications. On a PS3 emulator like RPCS3, the process is much more integrated. The software allows for patching game files directly and scanning memory values, giving players god-like control over their gaming experience.
Even if you have the correct cheats for your PS3 emulator, they might not work. Here is why: cheats for ps3 emulator