To directly answer your question: You can backup your PC game data. I don't believe you can backup your PS game data.
Security wise, if you can maintain a clean computer, they're equal, but if you're not very good at doing that, PS is the better option as consoles are harder and less lucrative to target with malwares.
That said, PC is always the safer option because you can upgrade your pc/replace it with a better one. In 5 years, if this game should last that long, it's tough to say / it's unpredictable / whether you'll be glad you're playing on a PS4 or if that system will be holding the game back.
Right now, just like PS2 and 3, the PS4 has amazing hardware and capability but it never seems to last as long as the hype promises.