Is nylon sheathing for DIY cables just window dressing?


Hi, quick question. Looking to make my own calbles, like the Mogami W3104 -12AWG 4 Conductor Speaker Cable material. It seems relatively easy to cut, strip cables into 2 separate right / left leads and add banana plugs. But every time I look for a little DIY u-tube education they all add the shrink wrap tubing and nylon sheathing to the assembly process. Is this really necessary? I can see where maybe using shrink wrap from the casing edge that was cut exposing the 4 individual leads and also having shrink wrap tubing over banana plugs to keep out air, but do you really need the fancy nylon sheathing? It adds about another $50-100 to the total cost. Thanks
128x128phill55
Good question. I have for years made a point of explaining how impossible it is to DIY cables that are as good as what you could buy professionally made for less than you spent on parts. But they never look as good either, and I never seem to mention that. They use better quality materials. Partly to protect the underlying wire, but mostly for appearance. If you don't mind the look, skip it.
Yes, more or less. They prevent the cable from looking bad when it abrades, but also the shrink wrap that does the transition from the nylon flex wrap to inside the jacks adds some strain relief, reducing the likelihood of a kink which impairs performance.
Understood, thank you for your response. The  Mogami W3104 -12AWG 4 Conductor Speaker Cable material is solid rubber with plastic sheathing underneath separating the 4 rubber coated conductor wires, so I thought I would jut shrink wrap tube the four two conductor wires into two and shrink wrap the banana plug to the wires to keep air out. This speaker cable seems to be really good quality at roughly $6 per foot. I think leaving the nylon sheathing would save me another $100 or so, given I need a 25' length from stereo to speakers. 
No, you don't need the fancy nylon braided sleeving, they are just cable dress up. A lot of high-end cable manufacturers use them to disguise the cable used underneath or to protect their method of construction and the material used, this is especially true when a cable is advertised as being hand-built or hand-made. The heat shrink used does provide strain relief where the connectors are terminated to the cable.