Unless you know exactly why you need the expensive one, you don't need it. Unless a reasonable-length cable is damaged or malconstructed in such a way that it

Unless you know exactly why you need the expensive one, you don't need it. Unless a reasonable-length cable is damaged or malconstructed in such a way that it distorts transmitted waveforms so much that they're not recoverable, any reasonable conductor will work. This stuff isn't rocket science since about a year after RS232 was invented.