Can you tell a difference between a FLAC file and 320kbps mp3's? Really? Honestly? I am not doubting you can. A lot of people can't and that is fine.

If you can, that's great. If not, there is absolutely no reason to get aftermarket cables.

If you can, then know that aftermarket cables will have an even more imperceptible better sound quality. They may be technically better (99.9% silver or whatever other marketing gimmick they will throw at you), but it will be extremely hard to tell any difference.

The only good thing about aftermarket cables is that it means you can replace your original cable if it gets damaged.