Is shielding cables that important?

Your question is much like asking whether automotive seat belts are important. If you need them, you had better have them. Many people live in areas where RF and EMI interference is not strong enough to require shielding. Provided other equipment in the system is not an issue, unshielded cables often sound better. Unfortunately, until you experiment, there is no way of knowing in advance. Your post indicates that you are extremely happy with your present cable, so I would leave it as is, unless you develop a problem.

Years ago I had this Kimber,KAGC /I thing those are the letters/ anyway,it's the braided no shielded cable.I never had a problem. Albert;when you're driving those soundlabs;you should have those seat belts on;air bags/ optional.

Van Den Hul makes cables both ways. "The First" cables are unshielded. "The Second" cables are basically the same construction but shielded. "The First" performs better in most opinions, so the shielding must have an effect on the sound.