Why is cable shielding important?

Answer 1

Cable shielding is important in guarding against stray EMI (electromagnetic interference). We don't usually operative in a vacuum, so there are various sources of noise, most commonly other appliances. If you're working near a motor, which generates a lot of ambient electromagnetic noise, you'll start seeing 60 Hz noise (the frequency at which our wall electricity operates) in your signal if your cables aren't properly shielded.