Insulation makes a difference, a rather big secondary influence. All types of dielectric materials interact and sound differently. Silk, cotton, wax, PE, cross-linked PE, Teflons, PO, PU, PVC, Nomax, Kevlar and on and on and on and on, all sounding different. Even color makes a difference to the sound as Stewart Ono in Hawaii taught Sean back before Zu was even born. Its impossible to say what is best as application, influence and target performance very. The reason many love the sound a wire insulated in silk soaked in pure carnauba might not be because of the silk.
Several years back a few cable “manufacturing” companies were marketing “no dielectric” for their cables, this is totally false marketing. There is always a dielectric, there is no lightning without the lightning bolt. Maybe they’re talking about pure music, were angeles insert the stuff directly into your soul. Sorry for “letting our kettle boil over” as Simon from England would say, but there is so much nonsense in the cable world and it’s hurting the industry that we love. Sure, the guy behind such marketing is likely interesting at a party (if he or she attends such things) but buying their product? Don’t do it.