Why do I need a switch?

I just watched a few videos about audiophile switches and I don’t understand the need. Cable comes into my home and goes to a modem and then a NetGear Nighthawk router. I can run a CAT6 to my system or use the wireless. If you don’t need more ports, why add something else in the signal path?  On one  of the videos the guy was even talking about stacking several switches with jumpers and it made the sound even better. He supposedly bought bunch’s of switches at all ranges and really liked a NETGEAR 8-Port Gigabit Ethernet Plus Switch (GS108Ev3) That costs $37 on Amaz.

Thanks in advance.